So I have a couple questions about druid Animal Companions. I couldn't find the answers in the books, so I'm looking to other people's house rules for a good answer.
1. Does a druid's animal companion have to fall under the same rules for wearing metal armor as the druid does, or can the companion wear any armor that it qualifies for?
2. Is there specific armor that is for animal companions or do you use the normal armor lists?
3. Does barding for animal companions encompass all the different armor classes, or is it just light armor?
I'm not sure Homebrew is the right section for your questions but I'll try to help.
1) Nope, they can wear any Barding they have the Str to use.
2) Yes they have specific rules and Armor they use and cannot use "normal" armor, look at the Barding Rules on the Archives of Nethys.
3) There is only Light and Heavy Barding so yeah, no "Medium" options.