Just a guess: Kalanchoe thyrsiflora 'Flapjack' (???) Somebody can verify or please ID correctly?
I agree with Mark; If you think mother plant is too big for being the top "tenant" on that "apartment complex" of a planter, you can clip the big stem and callous it for a few days and then try to root it. The remaining part of the rooted stem will hopefully send out one or two new heads. I would also wait for the existing offset to get bigger and longer stem before separating from the main stem. So there's actually 3 ways to propagate this "tenant".
