The unsprouted ones should be viable. The main problem is that a typical squash sold for the table is likely cross-pollinated; that is, it probably was grown within pollinating distance of different varieties of squash in the same species (there are three main species of eating squashes). Squash cross very, very easily and so the resulting plant grown from crossed seed will produce unreliably, you may get something that doesn't look like a butternut and may not be worth eating. Better to buy a packet at the seed rack and not waste space on a gamble, IMO...

I guess I just think of places like PA and NJ, and how they are farther south, and yet still zone 6. But admittedly I always forget to think of proximity to the water, and that would change things, so being on the island would make a difference. I googled, though, and found this. Who knows? I think you can find three different maps with three different results, lol. Not trying to be argumentative with anyone. I was just really somewhat taken aback when I saw Brooklyn zone 7. Sounds so tropical, lol. :) Dee P.S. Also interesting to see Suffolk county being zone 6. Must be elevation, I guess, but it is funny to me to see the north shore as zone 7 and the middle of the island as zone 6! Here is a link that might be useful: Cornell NY hardiness map

I read somewhere that the perfect stage to pick rosehips is when it's changing color from green to red-orange because it's easier to retrieve the seeds. More than that, I don't know. If I were you I'd hedge my bets, get some more mature rosehips and experiment with all of them. Have fun.

Great job, Leslie!! It’s very exciting!! I‘m sorry to hear about your mom, and I’ll also be praying for healing and a good visit. Keep us posted on your new baby! :-)