1) Fane. He has the most choices to make that are equally heavy. RP and Ifan has a clear goal, that's for sure.

2) Shield is actually best used on support mage becuse the AI will always make the best decision when attacking someone recklessly (Think Fire Emblem lunatic mode where they will rush the backline if they can get a kill because they lose nothing while you lose a guy) but if you plan on doing it, geo-warrior with warfare. Reactive shield just got nerfed btw so you can't rely on armor stacking + warfare + fortitude + reactive armor to kill a group of enemies anymore.

3) Ifan gets a free super strong crossbow (best one n Act 1) you can give to anyone though but you don't need to worry about that. The class itself is barely mentioned on anyone.