If you really wanted too, you could keep 100 2" discus fry in a 32 gallon tank...I have done it before. it all comes down to filtration and water changes...for the most part relying on water changes. You can keep 4 juvenilles in the tank, just watch for signs of aggression. That way, they would be cheaper for you and give you a few more fish to look at in the tank, lol. Just be sure you dont get them from your LFS as they are of MUCH lower quality and generally diseased and will die very easily.
Discus can be hard to feed...if they're not healthy. What most people experience is with bad or sick stock. If the stock you buy is from a reliable and reputable discus breeder/importer who knows what the hell they're talking about/doing, then they shouldnt have any problems what so ever in feeding. And another big problem that people run into with discus is not enough water changes. if you arent doing enough water changes, the discus will let you know by becoming dark, hiding all the time and eat very slowly or not at all. A healthy discus should be at the front of the tank or swimming around constantly....not sitting in one place behind something. A healthy discus should attack food like it's their last meal. If they dont do this, then something is wrong. Always, always, ALWAYS as a first line of defense when something is amiss with a discus is to increase the water changes. Discus can and will eat almost anything you put in the tank that is fish food...from flake food and pellets to homemade beefheart and red wigglers.
IMO, one of the best tankmates for discus are rams...they tolerate the same kind of water conditions and are very attractive. You can do angels, just be sure to clean the angels up for internal worms and bacteria first as angels *can* pass something onto discus. Dont worry about the angels pushing the discus away from the food...if the discus are healthy, they'll push the angels away, lol.
-Ryan