I believe most maples and sycamores are resistant to juglone, and pokeweeds are just unkillable.

Kentucky State U has a Pawpaw program that you might be interested in. They even have links to nurseries that produce seedlings, though I think they a) had a smaller-than-normal harvest last year, and b) are mostly sold out of seedlings at the moment.

I know biodiverseed has been working on a pawpaw planting project. There's a lot of interest in developing the pawpaw as a cultivated crop because they're the only custard apple species that is cold tolerant.