The bioload would be too high. To do this with sucess IMO you would need to upgrade to at least a 55 gallon. 2 dwarf angels would still be a problem, they would most likely fight unless it was a much bigger system. Even with a 55, I would stick to 1.
A 25 gal. ia a bit too small for a flame or a coral beauty. It might make a nice nano reef. I would say that your are almost maxed out with the two clowns you have in there. You could probably fit a goby or royal gramma as well. Good Lck...Lando