Don't get too hung up on the attacker/healer/tank/support tags. They're often misleading. Grand Master Yoda, for example, is a "support," but he hits like a train and is the main damage dealer on a lot of Jedi teams. Likewise, there are "tanks" that can't taunt and deal lots of damage. "Healer" and "Attacker" are mostly accurate I guess, though Visas Marr is tagged as a healer and seems more like a hybrid of both.
You're better off looking at each character's individual kit and figuring out how it would fit into a full squad - what does it counter, what will it synergize with, etc.