Whether you change from what I've recommended (as I do have multiple options for some companions) or you change them entirely. You can always change what each characters classes and roles are. In advance, I will say that this is suited to my play style, thus my opinion on what I think fits best with whatever. This was made for myself, but thought it would be helpful and cool for others to see.
This took me awhile but I felt this was necessary to do. To find all available companions in the game you open the in-game encyclopedia, go to Heroes, and then.A brief guide on classes, roles, companions and groups. Companions can be recruited at major towns in the tavern.All companions have an occupation of Wanderer. Companions are unique charactersthat can be customized by the player and sent on tasks.They can be assigned to lead parties, and they cost no influence when you ask them to join your army.