Wizards and Priest are just for cc and healing. And the game, at least in hard, is quite easy. Just send Edér first to tank everything, positioning yourself and throw **** from the distance. If you please, you can hire a paladin npc in the inn until get Pallegina; auras are useful.
There's a simple strat that works in almost every case, I would say. Send Edér to tank, then the paladin trying to not get more than one mob agro. Behind them, positioning Durance with the staff, between your frontline and the wizards. Then, you and Aloth just use your per encounter abilities, and ocasionally some spells for cc when necessary. You have two wizards. In lvl 2, you can have two blind spells in area. So, two wizards, four blind spells. That's very awesome. Also, get that ability, I don't remember the name, that is a melee stun. Is very usefull when someone go trought your fronline, like ghosts. Just stun it and send Durance or your paladin to tank it.