How to set up and manage subinventory/reserves for amazon and regular customers in the same Org?

Summary:

We currently have an org with a FG subinventory location that our normal Order Management orders reserve and sell from from. The problem began because we have a separate subinventory to hold strategic inventory and fractional boxes for Amazon sales. Unfortunately we have been unable remove the reserve from that subinventory as I understand that this control happens by org. This results in the regular orders reserving ecommerce merch from the sub inventory ecommerce.

The second problem is that we send to Amazon merchandise that is still in our books. We have them in a location called Amazon. This also forms part of the inventory in OM. Its like its on consignment but the consignee does not end up buying the merch.