Welcome!

You'll find a lot of info in the articles on the home page of this site, left-hand column.

1. The mylar/foil blanket will trap moisture, soaking your sleeping bag. Your body puts out a lot of moisture (technically called "insensible perspiration") at night, so your sleeping system needs to breathe. Those emergency blankets are strictly for one-time emergency use. I take one when dayhiking but never when going overnight. If your sleeping bag isn't warm enough, wear more warm clothing inside.

2. The isobutane/propane mix will work down to about 20*F, but when it's below freezing you have to prewarm the canister (put it in your armpit under your jacket and do a war dance to keep yourself warm) and keep it warm while it's burning. The alternative method is to keep the canister in your sleeping bag overnight when it's below freezing. Since you already need to do this with your camera and your water filter, the foot of your sleeping bag can get rather clunky! With canister stoves, a windscreen is dangerous because the canister can overheat and explode. All the manufacturers say never to use a windscreen for this reason. I do use a windscreen that goes about 3/4 of the way around the canister (so there's some ventilation) and frequently check the temperature of the canister with my hand to be sure it's not overheating. I am taking a risk, though!

3. If I start telling stories, I'll be typing all night!