diff --git a/src/components/admin/ManufacturerForm.tsx b/src/components/admin/ManufacturerForm.tsx
index 740ee918..0ffe469f 100644
--- a/src/components/admin/ManufacturerForm.tsx
+++ b/src/components/admin/ManufacturerForm.tsx
@@ -163,7 +163,11 @@ export function ManufacturerForm({ onSubmit, onCancel, initialData }: Manufactur
           {/* Additional Details */}
           <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
             <FlexibleDateInput
-              value={watch('founded_date') ? parseDateOnly(watch('founded_date')) : undefined}
+              value={(() => {
+                const dateValue = watch('founded_date');
+                if (!dateValue) return undefined;
+                return parseDateOnly(dateValue);
+              })()}
               precision={(watch('founded_date_precision') as DatePrecision) || 'year'}
               onChange={(date, precision) => {
                 setValue('founded_date', date ? toDateOnly(date) : undefined);
diff --git a/src/components/admin/NotificationDebugPanel.tsx b/src/components/admin/NotificationDebugPanel.tsx
index b03879a4..e02e6c03 100644
--- a/src/components/admin/NotificationDebugPanel.tsx
+++ b/src/components/admin/NotificationDebugPanel.tsx
@@ -9,10 +9,10 @@ import { supabase } from '@/integrations/supabase/client';
 import { format } from 'date-fns';
 
 interface DuplicateStats {
-  date: string;
-  total_attempts: number;
-  duplicates_prevented: number;
-  prevention_rate: number;
+  date: string | null;
+  total_attempts: number | null;
+  duplicates_prevented: number | null;
+  prevention_rate: number | null;
   health_status: 'healthy' | 'warning' | 'critical';
 }
 
@@ -20,11 +20,11 @@ interface RecentDuplicate {
   id: string;
   user_id: string;
   channel: string;
-  idempotency_key: string;
+  idempotency_key: string | null;
   created_at: string;
   profiles?: {
     username: string;
-    display_name: string;
+    display_name: string | null;
   };
 }
 
@@ -165,11 +165,11 @@ export function NotificationDebugPanel() {
               </TableHeader>
               <TableBody>
                 {stats.map((stat) => (
-                  <TableRow key={stat.date}>
-                    <TableCell>{format(new Date(stat.date), 'MMM d, yyyy')}</TableCell>
-                    <TableCell className="text-right">{stat.total_attempts}</TableCell>
-                    <TableCell className="text-right">{stat.duplicates_prevented}</TableCell>
-                    <TableCell className="text-right">{stat.prevention_rate.toFixed(1)}%</TableCell>
+                  <TableRow key={stat.date || 'unknown'}>
+                    <TableCell>{stat.date ? format(new Date(stat.date), 'MMM d, yyyy') : 'N/A'}</TableCell>
+                    <TableCell className="text-right">{stat.total_attempts ?? 0}</TableCell>
+                    <TableCell className="text-right">{stat.duplicates_prevented ?? 0}</TableCell>
+                    <TableCell className="text-right">{stat.prevention_rate !== null ? stat.prevention_rate.toFixed(1) : 'N/A'}%</TableCell>
                     <TableCell>{getHealthBadge(stat.health_status)}</TableCell>
                   </TableRow>
                 ))}
diff --git a/src/components/admin/ParkForm.tsx b/src/components/admin/ParkForm.tsx
index 5893893d..fd9c4b7c 100644
--- a/src/components/admin/ParkForm.tsx
+++ b/src/components/admin/ParkForm.tsx
@@ -375,7 +375,7 @@ export function ParkForm({ onSubmit, onCancel, initialData, isEditing = false }:
           {/* Dates */}
           <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
             <FlexibleDateInput
-              value={watch('opening_date') ? parseDateOnly(watch('opening_date')) : undefined}
+              value={watch('opening_date') ? parseDateOnly(watch('opening_date')!) : undefined}
               precision={(watch('opening_date_precision') as DatePrecision) || 'day'}
               onChange={(date, precision) => {
                 setValue('opening_date', date ? toDateOnly(date) : undefined);
@@ -388,7 +388,7 @@ export function ParkForm({ onSubmit, onCancel, initialData, isEditing = false }:
             />
 
             <FlexibleDateInput
-              value={watch('closing_date') ? parseDateOnly(watch('closing_date')) : undefined}
+              value={watch('closing_date') ? parseDateOnly(watch('closing_date')!) : undefined}
               precision={(watch('closing_date_precision') as DatePrecision) || 'day'}
               onChange={(date, precision) => {
                 setValue('closing_date', date ? toDateOnly(date) : undefined);
@@ -632,7 +632,7 @@ export function ParkForm({ onSubmit, onCancel, initialData, isEditing = false }:
           {/* Images */}
           <EntityMultiImageUploader
             mode={isEditing ? 'edit' : 'create'}
-            value={watch('images')}
+            value={watch('images') as ImageAssignments}
             onChange={(images: ImageAssignments) => setValue('images', images)}
             entityType="park"
             entityId={isEditing ? initialData?.id : undefined}
@@ -663,7 +663,7 @@ export function ParkForm({ onSubmit, onCancel, initialData, isEditing = false }:
         <Dialog open={isOperatorModalOpen} onOpenChange={setIsOperatorModalOpen}>
           <DialogContent className="max-w-4xl max-h-[90vh] overflow-y-auto">
             <OperatorForm
-              initialData={tempNewOperator}
+              initialData={tempNewOperator || undefined}
               onSubmit={(data) => {
                 setTempNewOperator(data);
                 setIsOperatorModalOpen(false);
@@ -678,7 +678,7 @@ export function ParkForm({ onSubmit, onCancel, initialData, isEditing = false }:
         <Dialog open={isPropertyOwnerModalOpen} onOpenChange={setIsPropertyOwnerModalOpen}>
           <DialogContent className="max-w-4xl max-h-[90vh] overflow-y-auto">
             <PropertyOwnerForm
-              initialData={tempNewPropertyOwner}
+              initialData={tempNewPropertyOwner || undefined}
               onSubmit={(data) => {
                 setTempNewPropertyOwner(data);
                 setIsPropertyOwnerModalOpen(false);
diff --git a/src/components/admin/RideForm.tsx b/src/components/admin/RideForm.tsx
index 083792dc..3c91d114 100644
--- a/src/components/admin/RideForm.tsx
+++ b/src/components/admin/RideForm.tsx
@@ -326,10 +326,10 @@ export function RideForm({ onSubmit, onCancel, initialData, isEditing = false }:
         _technical_specifications: technicalSpecs,
         _coaster_statistics: coasterStats,
         _name_history: formerNames,
-        _tempNewPark: tempNewPark,
-        _tempNewManufacturer: tempNewManufacturer,
-        _tempNewDesigner: tempNewDesigner,
-        _tempNewRideModel: tempNewRideModel
+        _tempNewPark: tempNewPark || undefined,
+        _tempNewManufacturer: tempNewManufacturer || undefined,
+        _tempNewDesigner: tempNewDesigner || undefined,
+        _tempNewRideModel: tempNewRideModel || undefined
       };
 
       // Pass clean data to parent with extended fields
@@ -492,7 +492,7 @@ export function RideForm({ onSubmit, onCancel, initialData, isEditing = false }:
                   // Show combobox for existing manufacturers
                   <Combobox
                     options={manufacturers}
-                    value={watch('manufacturer_id')}
+                    value={watch('manufacturer_id') || undefined}
                     onValueChange={(value) => {
                       setValue('manufacturer_id', value);
                       setSelectedManufacturerId(value);
@@ -557,7 +557,7 @@ export function RideForm({ onSubmit, onCancel, initialData, isEditing = false }:
                     <>
                       <Combobox
                         options={rideModels}
-                        value={watch('ride_model_id')}
+                        value={watch('ride_model_id') || undefined}
                         onValueChange={(value) => setValue('ride_model_id', value)}
                         placeholder="Select model"
                         searchPlaceholder="Search models..."
@@ -595,7 +595,7 @@ export function RideForm({ onSubmit, onCancel, initialData, isEditing = false }:
           {/* Dates */}
           <div className="grid grid-cols-1 md:grid-cols-2 gap-6">
             <FlexibleDateInput
-              value={watch('opening_date') ? parseDateOnly(watch('opening_date')) : undefined}
+              value={watch('opening_date') ? parseDateOnly(watch('opening_date')!) : undefined}
               precision={(watch('opening_date_precision') as DatePrecision) || 'day'}
               onChange={(date, precision) => {
                 setValue('opening_date', date ? toDateOnly(date) : undefined);
@@ -608,7 +608,7 @@ export function RideForm({ onSubmit, onCancel, initialData, isEditing = false }:
             />
 
             <FlexibleDateInput
-              value={watch('closing_date') ? parseDateOnly(watch('closing_date')) : undefined}
+              value={watch('closing_date') ? parseDateOnly(watch('closing_date')!) : undefined}
               precision={(watch('closing_date_precision') as DatePrecision) || 'day'}
               onChange={(date, precision) => {
                 setValue('closing_date', date ? toDateOnly(date) : undefined);
@@ -1390,7 +1390,7 @@ export function RideForm({ onSubmit, onCancel, initialData, isEditing = false }:
               <DialogTitle>Create New Designer</DialogTitle>
             </DialogHeader>
             <ManufacturerForm
-              initialData={tempNewDesigner}
+              initialData={tempNewDesigner || undefined}
               onSubmit={(data) => {
                 setTempNewDesigner(data);
                 setIsDesignerModalOpen(false);
@@ -1413,7 +1413,7 @@ export function RideForm({ onSubmit, onCancel, initialData, isEditing = false }:
               </DialogDescription>
             </DialogHeader>
             <ManufacturerForm
-              initialData={tempNewManufacturer}
+              initialData={tempNewManufacturer || undefined}
               onSubmit={(data) => {
                 setTempNewManufacturer(data);
                 setSelectedManufacturerName(data.name);
@@ -1442,9 +1442,9 @@ export function RideForm({ onSubmit, onCancel, initialData, isEditing = false }:
               </DialogDescription>
             </DialogHeader>
             <RideModelForm
-              manufacturerName={selectedManufacturerName || tempNewManufacturer?.name}
+              manufacturerName={selectedManufacturerName || tempNewManufacturer?.name || ''}
               manufacturerId={selectedManufacturerId}
-              initialData={tempNewRideModel}
+              initialData={tempNewRideModel || undefined}
               onSubmit={(data) => {
                 setTempNewRideModel(data);
                 setIsModelModalOpen(false);
diff --git a/src/components/admin/SystemActivityLog.tsx b/src/components/admin/SystemActivityLog.tsx
index ff191dfe..df4f490d 100644
--- a/src/components/admin/SystemActivityLog.tsx
+++ b/src/components/admin/SystemActivityLog.tsx
@@ -730,7 +730,7 @@ export const SystemActivityLog = forwardRef<SystemActivityLogRef, SystemActivity
         }
 
         default:
-          return null;
+          return <span>Unknown activity type</span>;
       }
     };
 
diff --git a/src/components/auth/AuthModal.tsx b/src/components/auth/AuthModal.tsx
index 3f416c66..5601fb05 100644
--- a/src/components/auth/AuthModal.tsx
+++ b/src/components/auth/AuthModal.tsx
@@ -126,7 +126,7 @@ export function AuthModal({ open, onOpenChange, defaultTab = 'signin' }: AuthMod
       const { handlePostAuthFlow } = await import('@/lib/authService');
       const postAuthResult = await handlePostAuthFlow(data.session, 'password');
 
-      if (postAuthResult.success && postAuthResult.data.shouldRedirect) {
+      if (postAuthResult.success && postAuthResult.data?.shouldRedirect) {
         // Get the TOTP factor ID
         const { data: factors } = await supabase.auth.mfa.listFactors();
         const totpFactor = factors?.totp?.find(f => f.status === 'verified');
diff --git a/src/types/database.ts b/src/types/database.ts
index a0a49ef8..332505a9 100644
--- a/src/types/database.ts
+++ b/src/types/database.ts
@@ -35,13 +35,13 @@ export interface Park {
   id: string;
   name: string;
   slug: string;
-  description?: string;
+  description?: string | null;
   status: string; // Allow any string from database
   park_type: string; // Allow any string from database
-  opening_date?: string;
-  opening_date_precision?: string;
-  closing_date?: string;
-  closing_date_precision?: string;
+  opening_date?: string | null;
+  opening_date_precision?: string | null;
+  closing_date?: string | null;
+  closing_date_precision?: string | null;
   website_url?: string;
   phone?: string;
   email?: string;
@@ -132,7 +132,7 @@ export interface Ride {
   id: string;
   name: string;
   slug: string;
-  description?: string;
+  description?: string | null;
   park?: Park | { name: string; slug: string; location?: Location }; // Allow partial park data
   ride_model?: RideModel;
   manufacturer?: Company;
@@ -140,10 +140,10 @@ export interface Ride {
   category: string; // Allow any string from database
   ride_sub_type?: string; // Sub-category like "Flying Coaster", "Inverted Coaster", etc.
   status: string; // Allow any string from database
-  opening_date?: string;
-  opening_date_precision?: string;
-  closing_date?: string;
-  closing_date_precision?: string;
+  opening_date?: string | null;
+  opening_date_precision?: string | null;
+  closing_date?: string | null;
+  closing_date_precision?: string | null;
   height_requirement?: number;
   age_requirement?: number;
   capacity_per_hour?: number;