Maybe try to thaw them in hot water in a baggy so the rodent doesnt get soggy wet, then when you're sure it's thawed, feed. I don't understand why you rinse the mouse under hot water. That probably rinses off some of that good smelling mousie scent to entice the snake.

As for the mouse losing heat as she constricts, thats normal. The reason to get them warm is so the snake will recognise it with the heat pits and constrict. Once they stike, it's usually a done deal that they'll eat it.