Frying hose with a heat gun or butane torch will ruin it...but WARMING a hose with a blow dryer won't harm it and will make it a LOT easier to get off the fittings.
Your entire post makes a much better case than I ever could for the value of thoroughly rinsing out the system as preparation for winter layup. There's NO excuse for any sewage to remain in the lines to dribble when you remove hoses...it should only be clean water...maybe only a little dirty from residue in the hoses. A plastic garbage bag is all you need to catch any drips. Y'all actually go out of your way to make rebuilding a toilet or replacing any hoses a far worse job than it needs to be...purposely, I suspect...'cuz after all, what good is doing it if you can't get a good war story out of it?