There are 2 pawpaw (Asimina triloba) species that do not take other grafts onto them according to KYSU research.
I thought somebody on this forum had successfully grafted cherimoya to paw paw?? Now, I have no idea what specific varieties. But apparently loquats can be grafted onto apples pears and quinces, and that’s pretty far out there... I must wonder who has time for all these strange futile grafting endeavors LOL
Seems the apple or rosaceae family things cross a lot
A intergeneric hybrid happens a lot in the rose family See pear x mountain ash berry = shipova (found hundreds of years ago)
(the latin name will have a x in front like this X Sorbopyrus auricularis)
As for hybrids of Asimina with Florida ones I'd be interested in that myself
One thing that I would be afraid of grafting is the graft might out grow the small Florida species ,
but I am really not sure just a possibility as it happens I hear with other stuff.
another interesting species in Florida is the 2 Deeringothamnus (beautiful Pawpaw)
Asimina manasota is said to be discovered less then 15 years ago so who knows what else is still out there.