Yeah it could be like when you leave your chocobo in the stable, you can't access it anywhere else unless you take it out again. So essentially you could assign a minion from your list that just does random stuff around your house/apartments, and considering how many minions there are anyway there should be lots of possibilities. Probably would need to limit it to a few minions max (maybe 4) being assigned to roam the house, you can bet SE will have some kind of server limitation to remind us about.