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've tried them all, and the jewelers tags work the best for me. I use a pencil to mark the pollen parent on the tags, pens and markers don't work as well. When I harvest the pods the tags go into the envelope with the seeds. I liked the wires, but, I would have to keep the key handy when I transfered the seed from the paper envelopes to the ziplocs. Then later they all need to be straightened, and sorted for the next use. The other problem I ran into was when a cross didn't take and the old bloom fell off sometimes the wire went with it and I was continually picking them up while weeding and putting down new mulch. The bread tags are ok, but on some plants they are hard to put on, and I broke off some flowers I had just pollinated while trying to put them on. You can reuse them if you use a pencil, or a grease or china marker. I use a damp cloth to get the pencil off, and some vegetable oil or a cloth with some WD40 on it to clean off the china marker, you have to scrub harder with the veggie oil. I still use a few of these for crosses involving seedling with long pedigrees. They all work well, but in my wifes eyes, the garden looks like a tag sale when I use the tags.

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.

I can only tell you my own experience with blue bonnets. We live in central texas, rocky, dry, etc. I planted the seeds in November, as recommended, only one time. In subsequent years I've had b.b. blooming from January through June. Take into consideration I have a strange back yard. The part nearest the house is the lower level. About 20 feet out from the house there is an upper level about 6 feet taller. There is a privacy fence around the whole thing. So, I think I just have different micro climates and they bloom sort of willy nilly. All of these areas, but particularly the lower level, are protected from the north winter wind. Sounds like that may be the case with you - having a bayou wall. Are you in southeast texas? I grew up down there but don't ever recall seeing blue bonnets. Seems like they prefer drier conditions, but it's been a while. I really don't think planting at different times will make a difference, but it can't hurt to try. The issue is sewing the seed when ground temps are correct. There is some growing info at the link below that may help you. Here is a link that might be useful: Native American Seed