Hi , first of all what is the temp of the tank? Discus like to be in the range of 28-30 .
A single discus in a tank is too lonely for the poor fish cos discus are schooling fish and so they do better in a group of 6-8.
Color bit is a good pellet which the discus will eat.
Keep an eye on the flying fox cos' they will annoy the discus by latching on to them.
Cardinal, Rummynose, bristalnose, loaches are allright with discus cos' they can handle the higher temp. Personally I would't put Gourami and Platty in with discus.
Hope that help and happy fish keeping.
Ronnie