On your question 2 I would ask why you want to use a steering wheel, since a leaning vehicle does not require any where near the amount of steering angle change as a vertical one does to achieve the same directional change. If your vehicle is a 3 wheel type that locks vertical at low speed and leans at higher speeds, I would suggest that handle bars are still the most logical control setup, as most riders are used to switching back and forth from steering to counter steering as the need arises.
When I was a kid, one of my friends got a bicycle with a steering wheel instead of handle bars. Some of us, myself included, couldn't even ride the damned thing, since we had already developed ingrained habits (we were all under 10 years old) that told us to turn a steering wheel in the direction we wanted to go, and to counter steer with handlebars. I think that this could only be worse now, with a lifetime of habit built up.