It depends on what kind of pleco you get

Most bristlenose get about 5-6 inches and do a great job of cleaning up algae an will also eat shrimp pellets, veggie wagers and just about anything that falls to the bottom.
You could have 3-4 corys but they won't cleanup any algae if you get any.
I have green neons and black neons with my angels and they do great. Those particular neons are too big for the angels to eat.
I think 2 angels are about all you want in that size tank.
Welcome to FishLore!!!!

We love to talk about our fish.
Carol