A) Is this true?
B) Does it matter if my liners are heat moldable?
C) What is good portable heater? Are heated boot bags good or is there a better choice?
I heat my boots this way. I pack them in my bags, drive to the ski area, carry them into the lodge and put them on, then go ski. It works every time.
If you really do want to heat your boots for a variety of reasons such as it makes them easier to put on, it is nice to start with warm boots, the heat kills the bacteria that keeps your friends from sitting next to you then buy a Hot Gear Bag.
If you want to heat your boots to improve performance use the method in the first paragraph.