The current tank temp is just under 80 degrees so I don't think it would be an issue to raise it another few degrees. All the fish you mentioned are quite big already. The bala shark is about 7 inches and the siamese algae eaters are around 4 inches. Regardless, I don't have anywhere to move them too. I live in a one bedroom apartment and I have a 120 gallon and a 10 gallon. I think that's enough tank for me. People already think I'm a bit crazy!
I know it's not the ideal situation for a discus but on a scale from 1-10. 1 being dead discus within a week and 10 being super happy discus. where do you think I land?