I don’t know the answer Dax, however, mixed ploidy levels are often implicated in graft failure. I’ve had serious difficulty getting a pecan graft to take on a mockernut hickory. While others have said it can be done, I interpret lack of success to indicate 64 chromosome mockernut does not like 32 chromosome pecan.
Cold tolerance is a different can of worms. (worms are great if you are fishing, not so much otherwise) In general, perennial trees grown in northern climates should be grafted on rootstocks that originated in similar climates. I would avoid southern rootstocks for persimmon given where most of yours will be grown.