I play two Capps.
and I've had threads with multiple chars in (Dieter and Pike, Dieter and Corvus... erm.. sure there was another...) which weren't classes/school things (those things included I've had orion, millicent, emily and alvin all in one thread before XDD that was exhausting). It'd just be sad if you were only playing by yourself.
Personally I like to see how my characters react to each other ic though. I can't wait for moira and dieter to be in the same thread XDD