I sold the Auxiliary console, realized the next day I should have kept it, and now can't get it back. could we have a shop sell it to us after we complete the order?

You can get another from the fun shop I believe

You can also purchase the Couch Set from the Furniture Shop and it comes with a half-sofa that you can set your Auxiliary on.

In addition to that, you can access your Auxiliary's functions directly from the Quarters Console without needing to have the Auxiliary Console.