Hmmm, I'm not seeing a ton of crossover just yet. For the new campaign, it's Orc only, with the Warrior classes and two Tinker classes available. At least the unlockable Warrior classes are kept from before, but I'm not a fan of the general class group - actually, Spellblade might be my favorite among those, and they don't seem to work well as Orcs at all.

Maybe the Yeti or whoever else will be able to play some other unlocked classes later on. I wasn't able to find info at this early stage, at least not on the wiki - forum goers might know more. I was expecting to be able to play cursed Orc of some sort, or maybe a mage - but maybe you have to re-unlock them. I don't know. I do know that enemy orcs used to be mages sometimes, but you can't start a brand new game as an orc mage right from the beginning.