i need help in creating a photoshop script.

i work in a retoucher environment for a large company. we get in product files as layerd .tif files. we have to put them on a 2000x2500 pixel jpg. the issue is, i need the top of the product to be a uniform distance from the top of the document and maintaini its proportions and positioning. some of the files have a transparent image lavey, a shadow layer with mask below that, a color fill layer below that, and an unused layer at the bottom. another variation is the have the top product layer in a group and the rest is the same .
Ive. been using a few AI tools and the path weve gone down is to
1. Resize the image to 2000x2500 if needed
2. Merge anything above the color fill layer, 
3. drop a horisontal guide at 675px (we havent determind the proper height we would need yet)
4. move the top of the product to meet the guide
5. Flatten and export or just export as aJPG

we tried flattening the image first, creating a new document pasting it in, and doing the remaining steps but cant seem to get it quite right. 

 i ould do it withan action, but dont know any way to find the top pixels of the product and bring it up to the guide or to a specific distance from the top
I am open to using separate scripts f need be. we process over 30k documents per year and if i can get this piece automated, it would be a huge help. any scripts gurus out there able to help me??