I havent personally tried keeping them together but someone else with more experience may be able to help you!
this is what i know anyways....
they require a high temperature of about 80F, guppys prefer lower temps and a higher PH to be happy, although you can keep them in a lower ph setup as with all other livebearers a higher ph is better
tanks mates sucker mouth catfish, cory's, tetras, rasboras. Shoals of tetras or similar will act as dither fish, making the discus feel more safe in their surroundings
since discus are cichlids they can be territorial especially when breeding, to defer bullying its best to have them in groups of 4, with 6+ being much better
they prefer an acidic PH to do well, so anything in the 6 range is good
tanks must be mature and stable with good filtration as they are very messy!