If provided room to hide from eachother they should handle it for the short haul. My friend had to treat her whole tank for ich. She had to place a naso tang and a chevron tang in a 55 gal with about 13 other fish. Lots of water changes were done and everything was given plenty of hiding spaces. No fish were lost and everyone made it through QT. They are now back in their 230 gal tank and happily swimming around. Fish will handle changes the worst is stress and desease. If you can minamize this then you should be able to save everything. You can also try some lace rock if you can get your hands on any since they will be in there for 6 weeks at least. This may help them feel better protected and usually doesn't cost an arm and a leg. It also doesn't hinder any treatment. Good luck, I do hope everything goes well and I am sending good wishes your way.