Temperature is fine as they dont need to be kept anywhere near as warm as people think they do except when spawning maybe, ph is ok for the hardier tank bred types... its the hardness you need to look at...
You also need quality (nitrates etc) to be spot on, if you live in an area where tapwater nitrates are 40ppm then i wouldnt bother...
Then you have to bear in mind they are cichlids and can be bolshy and aggressive in their own rights so no long finned fish like guppies and fighters....
But Discus have a tendancy to be big sissies and so you dont want boisterous fish liable to bully them so sharks, barbs,other aggressive cichlids....
And Discus are also more than happy to eat small fish... A lot of people keep cardinals etc in with discus but i would never risk it, all my discus ate cardinals or any tetra they could catch, they would pen them in the corner and pick them off.
So yes they can be kept in community tanks... if he community is designed with Discus in mind...