1.
2. doesn't matter, either way, as long as the tissue isn't stuck to the roll, where you have to fight with it, and end wasting half the roll unnecessarily.
3. After I leave the shower. When my feet are wet, I just step into one pair of slippers. After I dry my feet off, I have another pair of slippers that I put on. It's strange, but it works for me.
4. Both socks, then shoes.