Kis and szaladnak should be also accepted.
I wrote the word cicak instead of macskak (sorry, I don't have a keyboard for accent marks). Aren't they synonyms?
Cica is kitten, hence baby cat
Does mögött only mean that the cats are behind the mice? Or could it also have the other meaning of "running after something", i.e. "Chasing"?
although it can imply the action of chasing (as well as following) sby, for that you'd use "kerget", "űz" vagy "üldöz" instead.