Methanol will separate from gasoline in very cold temps, to what extent I am not sure. A lot depends on the amount of methanol compared to the gasoline and of course the temperature. Small amounts of methanol will remain mixed with the gas but some of it may separate if the percentage is very high. Gas line
antifreeze is straight methanol and is to be used in very cold temperatures but the average container size is just a couple of ounces. This small amount of methanol will easily mix with, and stay mixed with, a tank of gas no matter now cold it gets. Throw in a couple of gallons and it may be a very different situation.
I am only guessing now but I can not see any reason why a mixture of methanol and gasoline that has separated should not remix when warmed up. I used to race snowmobiles and I tried running a 50/50 blend of methanol and gasoline. Of course 2 cycle
oil was also involved. I gave up because it was just too much trouble trying to keep this blend mixed. Maybe I should have just reduced the amount of methanol I was trying to blend but I was young and in a big hurry at the time. I looked for other ways to go faster.
Wayne