Discussion that comes up constantly with our group as I'm a Gnome Illusionist with a weasel familiar, where my argument is constantly "no they can't even wear armor let alone magic items" but did some research and found out that they can in fact wear armor (if they are proficient in it) but the reason I ask is because of the feat "Extra Item Slot" listed as one of the feats you can switch out with your other familiar default feats that says "
Choose one magic item slot not normally available to creatures with your shape. You can now use magic items in that slot." but then reading under the actual magic item description for animals doesn't state anything about needing this feat in order to equip magic item's for the slot that they can equip them to.
So pretty much is that can they wear magic items with/without this feat and if so do they need to take this feat multiple times for each slot?