1) It supports up to 320K, even VBR (but not officially)
2) I think you can, but it requires some creative hacking.
3) Without trying it, you can click the first one, then shift click the last and it should have them all. (This may not be true, so don't quote me.)
4) When the loops are made within the loop editor, they loop properly within the software, but if you're talking about after you've exported, yeah, I know about this and it's already been suggested.