Yup, I can imagine adding them as a permanent companion later on! Then they can try to bad end us from the very start!
Well, of course... Being cute and fluffy is clearly an upgrade! And hosting a nice kitsune like that might have some side effects benefits... After all, who could say no to more fluffy tails~? And, it'd probably be easier to use any new kitsune powers without limit— Though, of course, your new friend is also very old and knowledgeable— The more integrated you get, the more they help you out by actively directing you. After all, why wouldn't you want to listen to the more experienced kitsune~? :3
Absolutely agree, since Kitsunes store their magic power in their tails, more and bigger tails are a fortunate unfortunate must have side effect. And that is very true as well. As you said, it's always good to listen to your elders, they have more experience so they surely just want the best for you~