If you get standard fins it should work out, many breeders keep breeding pairs in 20 highs, which are 16" tall. Veils need a bit more height, 16" seems a bit cramped height wise to me but people do it & it works out fine.
What you really have to worry about with 2 angels in a tank is compatibility/aggression issues. They may get along fine, they may want to kill each other as they mature. Best bet in a tank that size would be to get 4, as they grow see who gets along, and keep the 2 that seem compatable.
Tolak