Remember that whatever insulation you choose is only going to maintain the items current temperature a bit longer. It will not be generating any heatto keep it from freezing if it is already near 32f.

Water bottle - the 40f water you got from the creek will only stay at 40f if insulated and will start to drop from there depending on the outdoor temperature and amount of insulation.

Filter (the one you are not supposed to let freeze) - after filtering 40f creek water the filter elements are going to be 40f. If you put the filter in a Ziploc and next to your body you can raise its temperature with body heat. It will warm faster without any insulation blocking your body heat from warming the filter. Once warmed by your body insulation will help maintain that temperature but for how long? Tucking it in the foot of your sleeping bag without insulation will allow your body heat to keep it from freezing.

Food - whatever temperature your backpack was when you got done for the day and hung your bear bag is the starting temperature when you insulate it. When you wake up in the morning you could retrieve your bear bag and put whatever energy bar you plan to eat for breakfast in a pocket to warm it enough so you don't break your teeth.

Electronics - once again whatever temperature they are while carrying is what temperature they will be when you tuck them in the insulation. Your body heat (and stove) are the only heat sources you have.

Batteries - (do your own research) - I read, but don't recall where, that your battery is okay being cold as long as you are not using the battery. So the theory is if you let your battery get cold wait to use (recharge) your phone, etc. until the battery has been warmed back up.