It sounds like a very cool tank, but maybe not for what you want to do with it. Given the tank is 2.5 feet long, it must then be very tall. This presents an issue for reef lighting and almost assures that you'll need to use metal halide for anything but low light corals IMO. Also, although any 75 gallon is too small for a regal tang in the long term IMO, a 2.5 foot tank is not suitable for any length of time. Regals should have a 6 foot tank minimum IMO.
Still, this sounds like an excellent deal to me, and if you are willing to work with the inherent limitations of a tall tank (vs. a longer tank), then go for it!

The fish you listed other than the regal are good choices. You will only be able to keep one dwarf angel, however, so choose one you really like!