Create Custom Module(s) to sync Inventory across Ecommerce Channels

I"m posting on behalf of a small retail music store. My Concept is to use Drupal as a central hub to send and process API requests/hooks to sync Inventory between 3 shopping channels Ebay, Reverb, and Shopify and a physical store location's inventory. A CSV of the store inventory can be imported from an ftp server (probably using feeds) at a set interval. I need someone to help develop a custom module(s) to do this. We have an existing Drupal 7 site but this might be easier in Drupal 8 so I'm open to that.

The basic version (which is what i think I'm after now) would only be concerned with syncing the quantities of inventory across the channels. Creating/editing listings and orders would be handled outside of Drupal.

A full fledged version of the application might allow for creating/editing/managing the listings across the various channels as well as syncing orders etc. I was thinking it might be possible to build of off Drupal Commerce and use it as a central repository for creating and managing the products and orders.

We can discuss more details later.

Thanks,
Matt