The ink in newspapers is soy based and it should not be harmful to them unless they bathe in the ink. Aspen is fine though, its what I use. I think it looks better

With tubs, you will automatically notice no problem with holding humidity. You won't need to put the water bowl near the heat source. I would actually advise against putting it by a heat source because it can make all sorts of nasty things start growing in the warm water.