diff --git a/src/lib/submissionItemsService.ts b/src/lib/submissionItemsService.ts
index 6f9e7861..4d585a7c 100644
--- a/src/lib/submissionItemsService.ts
+++ b/src/lib/submissionItemsService.ts
@@ -2,12 +2,167 @@ import { supabase } from '@/integrations/supabase/client';
 import { getErrorMessage } from './errorHandler';
 import { logger } from './logger';
 
+// ============= TYPE DEFINITIONS =============
+
+type EntityType = 'park' | 'ride' | 'manufacturer' | 'operator' | 'property_owner' | 'designer' | 'ride_model' | 'photo' | 'timeline_event' | 'milestone' | 'location';
+
+interface ImageAssignment {
+  url: string;
+  cloudflare_id: string;
+}
+
+interface ImageAssignments {
+  uploaded?: ImageAssignment[];
+  banner_assignment?: number | null;
+  card_assignment?: number | null;
+}
+
+interface LocationData {
+  name: string;
+  city?: string | null;
+  state_province?: string | null;
+  country: string;
+  postal_code?: string | null;
+  latitude: number;
+  longitude: number;
+  timezone?: string | null;
+}
+
+interface PhotoData {
+  url: string;
+  cloudflare_image_id?: string;
+  title?: string;
+  caption?: string;
+  photographer_credit?: string;
+  date?: string;
+  date_taken?: string;
+  order?: number;
+}
+
+// Flexible entity form data that accommodates all entity types
+// This is intentionally permissive to maintain backwards compatibility
+// while adding type safety to function signatures
+interface EntityFormData {
+  // Common fields (not all entities have all fields)
+  name?: string;
+  slug?: string;
+  description?: string | null;
+  images?: ImageAssignments;
+  
+  // Park-specific fields
+  park_id?: string;
+  park_type?: string;
+  status?: string;
+  opening_date?: string | null;
+  closing_date?: string | null;
+  opening_date_precision?: string | null;
+  closing_date_precision?: string | null;
+  website_url?: string | null;
+  phone?: string | null;
+  email?: string | null;
+  operator_id?: string | null;
+  property_owner_id?: string | null;
+  location_id?: string | null;
+  location?: LocationData;
+  
+  // Ride-specific fields
+  ride_id?: string;
+  category?: string;
+  park_id?: string;
+  manufacturer_id?: string | null;
+  manufacturer_name?: string | null;
+  designer_id?: string | null;
+  ride_model_id?: string | null;
+  height_requirement?: number | null;
+  age_requirement?: number | null;
+  capacity_per_hour?: number | null;
+  duration_seconds?: number | null;
+  max_speed_kmh?: number | null;
+  max_height_meters?: number | null;
+  length_meters?: number | null;
+  inversions?: number | null;
+  coaster_type?: string | null;
+  seating_type?: string | null;
+  intensity_level?: string | null;
+  drop_height_meters?: number | null;
+  max_g_force?: number | null;
+  ride_sub_type?: string | null;
+  
+  // Company-specific fields
+  id?: string;
+  company_type?: string;
+  founded_year?: number | null;
+  founded_date?: string | null;
+  founded_date_precision?: string | null;
+  headquarters_location?: string | null;
+  
+  // Ride model fields
+  technical_specs?: Record<string, unknown>;
+  
+  // Photo submission fields
+  photos?: PhotoData[];
+  entity_id?: string;
+  context?: EntityType;
+  title?: string;
+  
+  // Timeline/milestone fields
+  entity_type?: EntityType;
+  event_type?: string;
+  event_date?: string;
+  event_date_precision?: string;
+  from_value?: string | null;
+  to_value?: string | null;
+  from_entity_id?: string | null;
+  to_entity_id?: string | null;
+  from_location_id?: string | null;
+  to_location_id?: string | null;
+  is_public?: boolean;
+  
+  // Allow additional properties for flexibility
+  [key: string]: unknown;
+}
+
+// Specific typed interfaces for function parameters
+interface ParkFormData extends EntityFormData {
+  name: string;
+  slug: string;
+  park_type: string;
+  status: string;
+}
+
+interface RideFormData extends EntityFormData {
+  name: string;
+  slug: string;
+  category: string;
+  status: string;
+  park_id: string;
+}
+
+interface CompanyFormData extends EntityFormData {
+  name: string;
+  slug: string;
+}
+
+interface RideModelFormData extends EntityFormData {
+  name: string;
+  slug: string;
+  manufacturer_id: string;
+}
+
+interface PhotoSubmissionData extends EntityFormData {
+  photos: PhotoData[];
+  entity_id: string;
+  context: EntityType;
+}
+
+// ============= MAIN INTERFACES =============
+
 export interface SubmissionItemWithDeps {
   id: string;
   submission_id: string;
   item_type: string;
-  item_data: any;
-  original_data: any;
+  item_data: EntityFormData;
+  original_data: EntityFormData | null;
   action_type?: 'create' | 'edit' | 'delete';
   status: 'pending' | 'approved' | 'rejected';
   depends_on: string | null;
@@ -310,7 +465,7 @@ function topologicalSort(items: SubmissionItemWithDeps[]): SubmissionItemWithDep
 /**
  * Extract image URLs from ImageAssignments structure
  */
-function extractImageAssignments(images: any) {
+function extractImageAssignments(images: Record<string, unknown> | undefined) {
   if (!images || !images.uploaded || !Array.isArray(images.uploaded)) {
     return {
       banner_image_url: null,
@@ -339,7 +494,7 @@ function extractImageAssignments(images: any) {
 /**
  * Helper functions to create entities with dependency resolution
  */
-async function createPark(data: any, dependencyMap: Map<string, string>): Promise<string> {
+async function createPark(data: Record<string, unknown>, dependencyMap: Map<string, string>): Promise<string> {
   const { transformParkData, validateSubmissionData } = await import('./entityTransformers');
   const { ensureUniqueSlug } = await import('./slugUtils');
 
@@ -440,9 +595,15 @@ async function createPark(data: any, dependencyMap: Map<string, string>): Promis
 
 /**
  * Resolve location data to a location_id
- * Checks for existing locations by coordinates, creates new ones if needed
+ * 
+ * SECURITY NOTE: Locations should go through moderation flow.
+ * Current implementation allows moderators to create locations directly during approval.
+ * This is acceptable as only moderators can call this function (via RLS on content_submissions).
+ * 
+ * For user-submitted locations in the future, they should be submitted as separate
+ * submission_items with item_type='location' and go through the moderation queue.
  */
-async function resolveLocationId(locationData: any): Promise<string | null> {
+async function resolveLocationId(locationData: Record<string, unknown> | undefined): Promise<string | null> {
   if (!locationData || !locationData.latitude || !locationData.longitude) {
     return null;
   }
@@ -460,6 +621,7 @@ async function resolveLocationId(locationData: any): Promise<string | null> {
   }
 
   // Create new location (moderator has permission via RLS)
+  // FUTURE TODO: Change this to submission flow for user-submitted locations
   const { data: newLocation, error } = await supabase
     .from('locations')
     .insert({
@@ -487,7 +649,7 @@ async function resolveLocationId(locationData: any): Promise<string | null> {
   return newLocation.id;
 }
 
-async function createRide(data: any, dependencyMap: Map<string, string>): Promise<string> {
+async function createRide(data: Record<string, unknown>, dependencyMap: Map<string, string>): Promise<string> {
   const { transformRideData, validateSubmissionData } = await import('./entityTransformers');
   const { ensureUniqueSlug } = await import('./slugUtils');
 
@@ -575,7 +737,7 @@ async function createRide(data: any, dependencyMap: Map<string, string>): Promis
 }
 
 async function createCompany(
-  data: any,
+  data: Record<string, unknown>,
   companyType: string,
   dependencyMap: Map<string, string>
 ): Promise<string> {
@@ -652,7 +814,7 @@ async function createCompany(
   return company.id;
 }
 
-async function createRideModel(data: any, dependencyMap: Map<string, string>): Promise<string> {
+async function createRideModel(data: Record<string, unknown>, dependencyMap: Map<string, string>): Promise<string> {
   const { transformRideModelData, validateSubmissionData } = await import('./entityTransformers');
   const { ensureUniqueSlug } = await import('./slugUtils');
 
@@ -689,7 +851,7 @@ async function createRideModel(data: any, dependencyMap: Map<string, string>): P
   return model.id;
 }
 
-async function approvePhotos(data: any, dependencyMap: Map<string, string>, userId: string, submissionId: string): Promise<string> {
+async function approvePhotos(data: Record<string, unknown>, dependencyMap: Map<string, string>, userId: string, submissionId: string): Promise<string> {
   // Photos are already uploaded to Cloudflare
   // Resolve dependencies for entity associations
   const resolvedData = resolveDependencies(data, dependencyMap);
@@ -723,7 +885,7 @@ async function approvePhotos(data: any, dependencyMap: Map<string, string>, user
   }
 
   // Insert photos into the photos table
-  const photosToInsert = resolvedData.photos.map((photo: any, index: number) => {
+  const photosToInsert = resolvedData.photos.map((photo: Record<string, unknown>, index: number) => {
     // Extract CloudFlare image ID from URL if not provided
     let cloudflareImageId = photo.cloudflare_image_id;
     if (!cloudflareImageId && photo.url) {
@@ -846,7 +1008,7 @@ async function updateEntityFeaturedImage(
  * Resolve dependency references in submission data
  * Replaces submission item IDs with actual database entity IDs
  */
-function resolveDependencies(data: any, dependencyMap: Map<string, string>): any {
+function resolveDependencies(data: Record<string, unknown>, dependencyMap: Map<string, string>): Record<string, unknown> {
   const resolved = { ...data };
 
   // List of foreign key fields that may need resolution
@@ -1021,7 +1183,7 @@ async function updateSubmissionStatusAfterRejection(submissionId: string): Promi
  */
 export async function editSubmissionItem(
   itemId: string,
-  newData: any,
+  newData: Record<string, unknown>,
   userId: string
 ): Promise<void> {
   if (!userId) {