Wharton does not transfer credit for classes elsewhere (although relevant prior classes may allow you to waive out of some core classes at Wharton, and replace them with additional electives).
Wharton does accept people with prior MBA's, but the closer your previous MBA studies are to the present, I think the harder it is to argue persuasively that a Wharton MBA is the best way to achieve your goals without making your decision-making look shaky.
You don't need grad courses to show you are capable of performing at a graduate level, just that you are smart and likely to apply yourself to your studies.Probably about 2/3 of successful applicants only have a Bachelors degree.
FF