So, if I have 10 pets while my GA is active but after it runs out I decide to adopt one of my pets out, would that eliminate that pet slot or would I be able to refill the 10th slot even though the GA is not active? and, do you get to keep your 5 extra pets once the GA time runs out? Sorry if this is super obvious aha.
You get to keep your extra 5 pets when you GA runs out. However, if you adopt out a pet, you won't be able to refill that slot without a GA. Some of us kinda call those 5 slots "GA Slots" since they won't be available without a GA.

@ Cia Hello! Here is a great FAQ for Gold Account questions. I don't mind answering any questions though! So you will never lose the pets you fill those extra slots with after your GA runs out but if you decide to adopt out or abandon a pet, you cannot fill that open slot without an active GA.
Hope this answers your questions!
Edit: Thank you for the explanation as well, !