A 55g isn't too small for either of those options. For 4 mollies, make sure you get one male and three females. The angels should be able to keep the molly population in control as they'll eat your molly fry, which is a good thing otherwise you'd have a tank full of mollies in a couple of months. I would get at least six cories. The more you have, the better, as they're really interesting to watch in large schools. For cories, you'll want a very smooth gravel or better yet sand substrate.
The only problem you might run into is that if your angels are males, they might not get along with one another, but buying them young might help with this. The parrots are more aggressive so there's no guarantees there.
Not sure if you're aware of this, but blood parrots are a man-made hybrid fish that suffers from deformities that can have negative impacts on its quality of life. Also, many of these fish (even the "standard" red ones) are injected with dyes to give them their coloration which fades with time.