Welcome to AA! Happy to see you here
Ok, sounds like a good stock, but there are a few erodes with your stock
Cory catfish don't like to be in small groups, you should have at least 4 in that big of a tank
Discus enjoy company
I really hope you are not talking about Chinese algae eaters, they grow huge, and they become bullies when they get big, they will harass your other fish, otocinclus sounds like a better algae eater
Welcome to AA!