No, I have to disagree with you there Abercrombie, discus are not usually shy fish. Most of the time they are the most active fish in the tank, as long as they have some cardinal buddies and some more discus buddies. Anyway, you really need to get like 3 more because eventually they will start to fight with eachother. You need to get a shoal so there is a pecking order and no one fish is picked on.
In my discus tanks i have the ph at 8.3 and they seem to do fine but they are still kinda small (3.5 in). In breeding conditions is really the only time when you need to lower the Ph. I do about 50% changes daily, except there is one tank i need to do 95% all together daily because it is overstocked. They like plant cover, roots, and driftwood. I personally wouldn't keep them with angels because angels are stronger swimmers, and would probably take all the food for themselves. There is also a myth that angels carry some sort of disease that is fatal to discus. I dont know about that one...
I feed mine bloodworms, beefheart, brine shrimp, discus formula, discus pellets (hikari & Tetra) and flakes.
Good luck,
Daniel