I have a question regarding the 2 extra shops or galleries you are able to have when you have a GA. I haven't been able to find a solid answer to it. I know you get to keep the extra shops/galleries after your GA expires, but I want to know if you're able to continue to add or remove items from them, or if you're stuck at being only able to remove items until you activate another GA.

You can still use them, but they drop to the non-GA item limits and if you delete any shops, you've got to wait to remake them until you get another GA