Re: Character don't support/attack
As Terminus said, make sure they are set to follow you or your tank, not defend, and not follow themselves (they will attack if you do this, just attack random enemies which may cause them to be attacked rather than allowing the tank to be the focus).
If you are a rogue and enter stealth, the characters will hang back until you attack or command them to attack. The Veilfire torch goes for anyone. Once the veilfire is lit, a warrior can create a torch from it, and they won't attack until they drop the torch, which they won't do on their own. It is best to make the mage who lit the fire drop the torch, then create a torch with your inquisitor.