most softies will mix it up fine. I have bunched them all together randomly over the years and the only one I ever saw irritate other softies was Kenya tree, and that was less than what an Aiptasia would.
it's when you start touching softies and stonies, you have to watch. (LPS=stony coral like bubble and candy cane, meat etc)
mushrooms kill stonies if they touch. ...seen too many quick frag deaths. sps and LPS alike, and they kill them fast. you can have shrooms under stony colonies. it kind of works out because the shrooms like the shade so they lay low.
other softies and LPS are a "case-by-case" deal zoos seem to be fairly mellow WRT ticking off stony corals. actually zoos hardly fight with anything. i've had leathers bumping elbows with caulastreas and frogspawns no problems.