Your LFS is fooling you quite some there.
For starters adult Angels will reach a size incl their fins of 10" and that'll make it pretty hard for them to even turn around in a 36g, ideally you'd wanna keep them in a 55g.
The Barbs need to be in groups of at LEAST 6+; and they may not nip now, but once they grow a lil your Angels will be a sure attach for them.
Cories are very sensitive fish and they need the security of groups and they should not be kept in less then 8!
Silver dollar are to be kept in tank 60g+ and in larger groups as well to avoid territory behavior matters.
Also some of the fish you have there pref soft water and others hard water - You will agree only one kinda water comes out of your tap....so what's your pH and hardness?
This all said, this tanks is a VERY unfortunate set up and here's what I'd recommend you to do
Bring the Silver Dollars & Barbs back to your LFS in exchange for at least 5 more cory that you already have. And dep on whatever your water is add another peaceful fish, eg more male swordtails to this set up.
I'm not telling you all this to be hurtful in any way, I'm just trying to guide you to a way of tank set up that will NOT cause you major headaches and frustrations few weeks from now.