I can easily see quadrupeds driving! I don't see why people can't, all they'd do is stand on their hind legs and gold the steering wheel with the front legs. Easy!
Like characters who'd never had seen vehicles before? Mulan, the pirates, Lone Ranger, Tonto, The Emotions and more have all never driven vehicles before but they can in the game! I think Simba would be able to.
No, the characters will stay the same level as they were in 2.0. They don't have to be level 20. So if Merida for example is level 10 in 2.0 then when you place her down in 3.0 she'll still be level 10.