I second hikermor's suggestion to choose your site well.

I always use at least two sleeping pads, one closed cell-Thermarest and a cheapo blue pad, along with a mylar blanket underneath and a wool blanket to go over my cold weather sleeping bag, I'm usually toasty warm.

We eat a hot, high fat snack right before bed too, to get the internal furnace going. bacpacboy particularly recommends a hot chocolate and hot dog and/or cookies/smores. This mama likes a shot of kaluha in hers. A wool watch cap and socks, along with good old johns, always serve me well, even with an arthriticy hip.

Not sure about your troop tents, but ours were too big for a long time, for winter camping. Bigger, higher domed tents allow the youth lots of room, and tend to be more budget friendly, but makes for a lot of dead air space, which I find makes it cooler than in a smaller tent. Our group has upgraded to smaller Eureka tents now, and get fewer complaints about sleeping cold. (Let's face it, someone's always going to complain.)