I'd stick with mice and rats.
As for the bedding.
Well I have used aspen, news paper, and paper towel before.
From my experience I think that aspen is the best substrate that you can use.
It's a bit more costly compared to the others but then the smell does lower a bit. So I like it a lot more. Plus poop, water spill, and other stuff could be absorbed by the aspen and it's easier to clean up. So I would recommand using aspen
I am trying out a new bedding right now.
It's called alpha chips and the other one is called beta chips.
These two chips are just basically hard wood shaved into little pieces. The alpha chip is a lot lighter and flaker and clumps up a lot better. The beta chips is heavier, no dust and it does stain the water bowl if any where to get into the water bowl. But from right now I like the beta chips more than the alpha chips...I don't like dust...and I think that they're better and cheaper than the aspen~~