To answer question 1: I got a plastic lid for my Snow Peak 450 (which doubles as my pot) so I didnt burn my lips. What I realized what that if it was too hot for my lips, it was usually too hot to drink. Once the liquid cooled enough for me to drink, it was cool enough for my lips. I do still have a metal lid that I use while cooking, since cooking with a plastic lid can melt it. YMMV, of course. So I dropped the lid from my pack. One less ounce, one less item.
#2: You can buy Reflectix at a hardware store, which is basically tinfoil and bubble wrap that is used for insulating piping and ductwork. They sell tape for it also. You can make any size cozy you want! But I ended up dropping the cozy also, as I just didn't need it for my cooking style. The mug stayed hot enough to hydrate my meals.
Disclaimer: I hold no responsibility for anyone burning the crap out of their lip!