Re: Question about flannel liner
I would say no on the quilting, hedgehogs have a problem with getting their toe nails caught in threads, even possible of loose threads wrapping around their legs and cutting off circulation. I'm assuming quilting means you'd run a stitch line across the liner which in the end would create squares, and also exposed thread seams. Billowy I don't think would be too much of a problem for them, they can be fast but they'd probably just plow through any billowy area. I'm not sure since most owners use Fleece, flannel I think is #2 on the list of materials that can be used.
The purpose is to give the hedgehog something other than a plastic tray to run on with their little feet. Absorbency I don't think is a major factor in liners, fleece doesn't really absorb fluids like other materials, more passes through it. Its more just something soft that they can run on.