Clark, JF&E is a great nursery in my opinion. They send out big healthy plants that are potted and don’t suffer transplant shock. Few nurseries do that. But l learned the hard way that it’s also important to keep in mind that they’re located in Florida and so their rootstock hasn’t been tested up north. I believe they graft all their persimmons to D. virginiana rootstock, but not all D. virginiana are hardy to zone 6. I think it was a Sheng I ordered from that the rootstock died when it was -14 or so one year. I’d encourage you to think about burying JF&E’s persimmons with the graft union below the soil line. I’d also echo what @Barkslip said about letting your trees get a little meat on their bones before completely leaving them to the elements. Persimmons seem to get more cold hardy the older they are.
I’d bet you could do Rosseyanka, and JT-02, and may Kassandra, but not Nikita’s Gift. NG just doesn’t seem to be as cold hardy as many of the nurseries claim.
You could also consider growing persimmons in containers. @tonyOmahaz5 started a good thread on that topic a while back. Container Grown Kaki Persimmons