im with jlc on the feeding in seperate rooms on a time schedule.
ive always fed my kittens soaked kitten food at first and then just regular kitten chow when their teeth were strong enough.
about the litterbox, if you diligently keep it clean the apartment wont smell bad, also use a specially strong odor absorbing litter not the cheap stuff that "claims" to be odor absorbing. i always used something with arm & hammer baking soda for example. that stuff was great!