the hairless rats tend to have an even lower immune system then their furred counterparts so a simple minor myco flare can be even more dangerous for them.
i've also noticed a higher insidence of sudden death with hairless rats then i have with furred but i'm only going off experience there. sudden death is likes SIDS. before you go to bed they seem perfectly normal then in the morning you find them dead with no apparent cause. but again, i'm basing that solely on my own experiences with friends who have had hairless rats. they could have missed some early sign of illness, you never know.
as far as daily specail needs there really isn't much. don't take them out in the sun as often perhaps as they have no hair to guard against sunburn.
the temperature can be a concern in the winter if the heat goes out but so long as everyone else is comfy in there with the normal amount of bedding the hairless should be too.
i give my hairless a bath with all the others and she's fine with it so long as the water temperature is nice. think about washing a baby and don't get the water too hot or cold and that seems to be just right for the rats too.
i don't trim my rats nails (they have a lava perch to do that themselves though its not all that successful) and i've never had problems with my hairless getting sctratched up by the others anymore then the furred ones do. however you do notice the tiff scratches more on the hairless then you do on the furred and without that fur there it sometimes looks a whole lot worse then it really is but that's just appearances. if you have a white rat (or a rat with white on it) and give it a bath after a tiff you'd notice the same amount and serverity as you would on the furred ones. there really isn't much difference there. you have to keep in mind that though they don't have fur they still have really loose skin.