As for #4, all of my kids ended up in my cabin because the snoring was too loud in the other cabin. We had connecting cabins, so they would just enter through the other cabin.
We just did this exact thing. Two of my children were registered in their grandmother's cabin. When you do the online check in, you select all of the people you want to be charged to your account.
My daughter is 14 and will be 15 in Sept. Shall we exchange info so they can chat in the weeks leading up to the cruise?
Jodesta, our cabins are really close to each other! We are in 6086 and 6088.