Can you remove a level

1. As far as I can tell, the VIPs are indeed random, with perhaps a slightly higher chance to yield Supply Officers. Unfortunately, they'll only show up when you're actively playing, so it might require more real time invested than you're willing to, and there's never a guarantee that any particular one will show up.

2. Imperial floor missions start small, but soon become hugely rewarding; the one I'm currently working on gives a reward of 50k, and previous ones have been in the 75-80k range. However, there's not much point in building Imperial levels until the mission asks you to, and it can be frustrating if you're asked for a specific one but the levels you build turn out differently several times in a row. In that case, it can be worth skipping a mission for a few Bux and getting something you're better equipped for.

I have scowered Tiny Death Star, and as of version 1.1.2144 it looks like you cannot recycle a floor. The only way to attempt at getting another floor would be to delete the game and start over.