If it’s just passed it’s MOT, the bodywork is probably just cosmetic, and not too bad. But it will need sorting out for the future.
Sprinter 208 is very reliable. I had one for years. It’s quite slow though.
Nothing too much to worry about.
You don’t need seat belts if the vehicle has been converted.
However, your insurance company probably wont cover you if passengers are not wearing seat belts, and the police probably wont be happy either.