My thoughts and experience as well while I was with Stan Stevens and MMO. I hunted Dall, caribou, and moose at the same time you're going
Try on as many different boots as you can. Thats the only way to do it. Be prepared to order a bunch online and have to ship them back. Having the wrong boots will directly impact your hunt more than anything else. You dont want any blisters. I have had great luck with the crispi boots as well. I have i think 4 different pairs. Youll be in the nwt with the lancasters so your not going to be putting on like 20 miles a day hiking. I wouldnt worry about insulated boots to be honest. When your moving, everything warms up fast. your feet are still going to be sweating like crazy. I bring different thickness wool socks on my hunts and weather them due to conditions. If your in doubt on what to bring, just call Clay and ask him. Hes a great guy! Its a helicopter hunt so you can bring more gear than you would on a backpack sheep hunt also. Buy a caribou tag if you can.... there is less and less opportunities to hunt them