Why don't you start over in the spring and not worry about overwintering the cuttings? They are not going to thrive over the winter, no matter what you do.

Actually, while doing research on these cuttings, I learned that they should be done in late june/early july. I did them in later july, so im not that far off of the mark. They still have a few months to develop a root system in the sand and possibly in the media mix if i decide that is the route to go. Would it make sence to just plant them in the ground after a decent root zone has been established and hope for the best over the winter? or take more drastic steps to ensure their survival?

Your first freeze comes awfully early that far north. Do you have any way to keep them indoors over your long winter?
If you took a number of cuttings, what if you planted half in the ground and tried keeping the other half alive indoors until planting time in the spring? I think it is important that they go in a good potting mix or into the ground as soon as possible. Sand is acceptable for rooting, but it is a poor medium for growing, even with supplemental fertilization.