Elgecko - very organized, nice website. Nice plant tank too. As far as temperature goes, you may be able to keep the water at 80 degrees which your discus should do fine in. It depends in part on the health of your fish and genetic robustness. If your plants start suffering at 83 degrees, try turning the temp. down a bit and just keep an eye on your discus.
Several years ago I used to keep discus in a big way and bred them in a limited capacity for fun. They are absolutely my favorite freshwater fish to keep.
So far in my 90g planted tank, I love the rummy nose tetras. Man, do they swarm food and will stuff themselves until they're bellies are round which makes them look funny. Very active swimmers and they stay in a school mostly which is cool. I must say I'm very surprised at their coolness factor. I was going to add cardinals but then liked the way the rummys move. They are much more "wiggly" when they swim compared to cardinals, and follow me as I walk by the tank.
I have a silver hatchet too. Do you still have yours? These are legendary carpet surfers. Because my tank is frameless, I keep the water level a few inches below the top of the glass which keeps the hatchets in the tank. They love to stay in a constant mild current at the top of the tank. Not much personality, but very neat fish.
Now, if I can just get hold of a healthy batch of true altums.... (sorry, I'm wandering...)