Im guessing the HTR 7000 or MPX might fit better than the others? But i dont know. Also, would it sound better if I put them in the walls as opposed to the ceiling? Like up high?

If you don't like the idea of the surround pointing down directly above your head, the HTR-7000 would be the best choice. That said, many home theaters (especially smaller bedroom ones) use a standard in-ceiling (like the Invisa 525 or 650) for surrounds without complaint.... it is a fairly popular solution.

Yes, MPX up high on the wall is a "preferred" solution.

What is the angle of the HTR-7000

Approximately 30 degrees.

If I use two Invisa 525s what would be the best place for the surrounds in a 5.1 system? As in, ceiling, back wall, sidewalls? and where exactly? I read somewhere that surrounds should be about 2 feet above your ear level?