3 of us hunted Caribou on the N Slope of AK in late Aug about a decade ago. Temps were high 30's to low 40's at night and upper 50's low 60's during the day. My only real suggestion would be a 2nd tent to hang gear in. 3 people sleeping in a tent puts out a lot of humidity. We didn't have any manner of heater, just sleeping pads and sleeping bags.
If going someplace I could drive and didn't have to carry everything, I'd definitely have a "gear tent" and a "Sleeping Tent".
