When you have a GA and use a Mystical Plushie or the Pet Slot Totem to get an 11th pet, then abandon one of them later, do you go back to having 10 Slots, or is the 11th+ always gonna be there?

They're permanent. Only thing is, if you abandon your 11th pet and don't have a GA activated, you won't be able to get another pet until you activate a GA.

Ah, that's fine. ^^ Thank you. =)