So it states an ally can use your animal companion as a mount, if you do then who is using the actions to control it? And during whose turn does it go? If the rider is using their action to control it is it still considered a minion for them?
Also in regards to when companions act (not mounted in this question) can you split up the actions? Such as You use your stride action to move into range, you command it to stride into a flanking position, then you attack and then it attacks or must you use your 3 then it's 2?