[rjy9343]

Can you take them to a beauty school? It would be money, but it would get their haircuts at the same time and then you could deal with the baths without the hair cleanup.
If that's not a possibility, then I would deal with M first and have G clean up the hair while you bathe M. Take G with you if needed. I would also sweeten the pot and offer some sort of reward for his help. You know your son's currency, so I would do that and add more to it the more help he gives. Ivy gets extra privileges as well as spending money so I can get other things done and it's the only way I can make it through the day sometimes.
Then V and again, G cleans up while you bathe V. Then G and you clean up while G bathes.
The mess is something I totally understand, I shut down with that kind of thing as well and really struggle with it. Maybe cutting it on a plastic table cloth in the bathtub so that you can roll it up and throw it away. Then a quick vacuuming the bathroom.