So from that perspective, it would be entirely legal for a type rated 737 guy to buy a 737, and give "adventure" rides, letting anyone fly in the right seat, with passengers in the back. But oops, the aircraft is certified for two pilots.

At a minimum, the right seat needs someone with AT LEAST a MEL rating. AFAIK, the guy in the right seat of this show has NO rating at all. He may have an SEL.

I may be completely wrong, and confused. How can an aircraft that is certified for two pilots, get by with only one?