I can understand that fylimar. I only create male characters unless you can also make a custom companion.
I can see Wyll as a sorceror but I'm a sorceror so I gave him a bit of Wizard instead. I feel like he's smart and he would start exploring other ways of using magic trying to get out of the pact.
I wouldn't make Karlach feel bad or send Wyll to hell for all the tollkeeper's gold. If we can't get Mizora this time it's fine. We can wait...
I was trying for a build, that would focus on his swordmanship - since that was his (very cool) introduction. So I thought paladin fits. Another good class for him would be sword bard, because of the flourishes, that replenish on short rest like his warlock spells, but since I often play bard and don't like to main paladin - and don't have Minthara in the group, because I don't like to play evil - , I decided to go the paladin route with him. Fighter would also be a good fit imo, might try that next time.