Gotta agree with what was said...that Angel will get BIG, but if a 200g is in the works, it should be fine for now. I would wait in the Yellow Tang, as the larger tank will be better for it. There are Tangs that will work for a 75g though, so if you've got to have a Tang now, there are possibilities. Live aquaria.com has great info on specifications for fish (and compatability).
Keep an eye on you parameters. 0 nitrates but some nitrites is odd. Trites will turn to trates. So many fish, so fast is going to add lots of ammonia and if there are not enough BB, then things could spike quickly.