Dear Sir,
I used to work on eBay & Amazon APIs and have the CompleteSale API script for Update Tracking no, mark as shipped, also have the script for update the price, Stock and other listing information using ReviseItem eBay API call.
I have the Amazon MWS script for get details for ASIN using "GetLowestOfferListingsForASIN" MWS product API call, using this can get the FBA/Non Fba items, Seller Amazon or 3rd party and all the details that you mentioned in description. I can show the demo of my tools related to this as well.
Please discuss with me in details, I am looking forward your reply.
Thank you
Regards.