I gotta begin again with the hybrids besides Chuchupaka or JT-02. I had them on southern rootstocks, native seed of, Georgia. They didn’t make it thru the winter, two years ago when the low was like -6 but definitely warmer/under -10 F.
I planted about 2/3’s on southern rootstock including American persimmon cultivars. None of them made it thru the winter.
I believe @tonyOmahaz5 said JT-02 produces after -22 F and I’ve had (2) of them (JT-02 aka Mikkusu) die to a few inches above the graft union at -30 to -33 F during the 2018 polar vortex that I was near the eye of. They re-shot and are looking good, again.
Chuchupaka has now gone thru -9, my low this year.
Kasandra isn’t very hardy. It’s about a -11 tree or thereabouts if @SMC_zone6 tree was on northern roots. He lost his Kasandra at -11 near Boston MASS.
Rosseyanka isn’t hardy in zone 5b in IL. It’ll try to come back and does for 3-years and then it dies again. I live in a great 5b where -12 is the norm, annually. The very-coldest I see is -18. It’s a great trial place for zone 5b.
Nikita’s Gift is zone 7. 6b might do it for Nikita’s Gift but it’s a true zone 7.
NB-02 aka Zima Kurma has the genetics of: Nikita’s Gift x (kaki) Taishu. That’s not going to be very cold hardy.