all im saying is your lucky so far, at the end of the day fish dont know what kind of requirements they need and they dont know they are going to grow too big for a tank. These rules are basically a middle point where fishkeepers have agreed it is fair for fish to be kept, minimum tank size and correct numbers of schooling fish are probably the most basic ones for you to follow and something you should have been thinking about when you bought the fish.
Your not going to have issues with the danio or angels getting to big right now but in under a year they will, I used to keep angels about a year ago and mine got from .5 inches to 8 inches tall and long in a little over a year just to give you an idea of their growth speed.
I still stand by my original advice though if the tank is 18 inches tall rehome 2 of the angels, rehome the danio and add 4-5 more panda barbs. If the tank is less than 18 inches tall rehome all of the angels, rehome the danio and add 4-5 more panda barbs.
Wills