Well, since you had to ask...
1st, I'd NEVER place my water bottle in the fire, even if it could handle it. Sudden temperature extremes could warp the steel, causing the lid to not seat right ever again! Also high heat can eventually burn through the steel as well. Remember, in the land of Murphy there is but one law!
2nd, you've just limited yourself to only being able to cook & consume only one item at a time! Do you want coffee or supper? With a 32 oz. hard plastic Nalgene bottle you have graduations on the side that give you your liquid measurement. With the steel cup that fits over the end of the water bottle you have graduations for your dry measurement. You can heat the measured amount of water in your pot for your freeze-dried meal while measuring out your water for your coffee, tea, etc.. When the water for din-din is done you can add the water to your freeze-dried meal pouch and start your drink water going, allowing your food to absorb the moisture and even cool a bit!
I have the large Maxpedition water bottle carrier and, like Ranger, can store a lot of extra supplies in it. Just my "duos centavos." :cool2: