If your parents love it that much, and you guys love it that much, and you can teach your parents how to care for it when you guys aren't living at home, then go for it. Maybe it is the right tank for you, and it's neat that your whole family is going to be involved with it. You could save quite a bit of money by upgrading the tank you have now, since you've bought live rock and some fish and coral already. Then maybe sell off your 30 gal setup and use the money toward more fish and coral.
I really would not recommend putting a tang of any kind in a 3 foot tank. Maybe that makes me the tang police, but I've talked to plenty of customers that tried it and had problems during my lfs employee days. A stressed fish is an unhealthy fish.
As for the bicolor angel, it would not be a good choice for a reef IMO. Even if it doesn't start nipping at your coral at first, it probably will. I'm speaking from experience when I tell you it is not fun to tear down your tank to get an angelfish out after it starts eating your coral (and I promise it will be a tank teardown to get it out). In addition to the angelfish not being reef safe, it can also be difficult to feed IME.