AI Character Replacement in Existing Video Ad

I have an existing video ad and need it modified using AI video editing. I do not need a new script. I want to keep the existing dialogue, voice/audio, flow, scenes, pacing, and overall structure as close to the original as possible... (Budget: ₹600 - ₹1500 INR, Jobs: After Effects, AI Animation, AI Content Creation, AI Image Generation, AI Video Editing, Animation, Video Editing, Video Production)