I think wheel colliders would be fine as a start, but you're almost definitely going to have to do a certain amount of "fake" physics tweaking to get the bike to stay upright, and to get it to lean the correct amount to give a realistic turning effect, because it will be incredibly difficult to make it maintain these positions as a natural emergent result of the physics engine.
This means you probably can't just let the user apply force, and steer the front wheel. I think you're going to have to implement virtual training wheels of some description!
