Standard fin angels will get 8 to 10 inches tall, 6 to 8 inches long. Veils tend to have a smaller body, but much more fin, they will get 12 to 14 inches tall, 8 to 10 inches long.
Their growth tends to slow down as they get older, they get to their maximum size from 12 to 18 months, but will continue to fill out, getting thicker for another year.
50 gallons is fine for 2 angels, you could fit 4 or 5. 2 would work out nice as a centerpiece, only time will tell if the 2 are compatable long term. Even breeding pairs can get aggressive with each other, sometimes to the point of injury or death of the partner.
They are new world cichlids, and do have the preditory nature & aggressiveness associated with cichlids, though usually not as much as some of the others. They are classified as more of a semi-aggressive, and can usually be kept with other more peaceful fish in a larger community tank. Many livebearers are a good choice for tankmates, as long as they are large enough not to fit in the angel's mouth. Angels can open their mouth twice as large as you think they can, you won't have to worry about being overrun with fry from the livebearers.
Tolak