Carnival has changed their policy just this month on minors in cabins. I have 2 teens in a cabin for our cruise in Sept and called to check to make sure our booking was still ok. They said we were protected under the grandfather law since we were booked before the new policy came out. The old policy was kids could have their own cabin as long as they were linked to their parents booking. Now one parent, guardian or grandparent over the age of 25 has to be in the cabin with the kids so I don't know how you can do the cabins the way you want to. If it was me, I would put the moms in the kids cabin with one kid and then the dads in the other 2 with the other 2 kids and when you get on board just switch rooms. I would think you would all need to board at the same time but I could be wrong on that. I'm sure you will get alot of great advice on this board and somebody can answer that for you. Call Carnival or your travel agent to find out for sure.