I also suggest using a TA, preferably one who specializes in
DCL bookings, for this type of booking. I always book WDW and pretty much all land vacation myself. Cruises are a whole other ballgame to book. Since this is your first DCL, first time traveling with kids and your looking at booking two cabins across the hall from each other an experienced TA will be extremely helpful. We have three children, two are in college now and one is a teen but we have done several DCL over the years and most have been booked with the kids staying across the hall from us. Yes, one adult must be listed on each room, no one cares who sleeps in each cabin. Yes, they will issue a blank room key.
Please keep in mind that which ever adult is listed on the cabin is responsible for the minors listed in their cabin. This gets tricky because only that person is technically able to take the minor off the ship in ports and sign them out of the kids clubs. For kids clubs when filling out paper work online you can list who is permitted to sign the children out and you will have to develop a password that anyone who is permitted to pick them up must use. To take a minor off the ship you will need to have the person listed on the cabin with the minor sign a document (available at guest services )that allows the other adult to take the minor off the ship. It's odd to have the child listed in your cabin need you to have to sign this document to have their own father take them off the ship but it's just how the system works. Also, since one biological parent is not traveling with your party it will be necessary to have the parent not traveling with you sign a notarized document letting Disney/Customs know that they have knowledge of the child traveling out of the country with both Dad and you listed. I have done three DCL with my Mom and kids without my husband, who is my children's biological father, and I was only asked once by Disney and once by customs for this form but I was awfully glad I had it when asked for it. A good
travel agent should be able to advise you about how to go about obtaining all documents needed.
Also, if passports are going to need to be obtained for minors both biological parents must be present in the passport office or a notarized specific document by missing parent must be presented during the application process. You mentioned traveling this July so I would suggest starting the passport process now if they are needed. This can take time to arrange a schedule where both parents are available. I also just found out two weeks ago when we went to renew my 14 year- olds passport that in our area of Sarasota/Breadenton, FL that our passport offices were not open on weekends and most were only opened 10-3 and only accepted appointments. We have one office in downtown Sarasota that did walk ins and was open 9-5 but I do suggest looking into this soon because we ran into issues trying to find a time that worked where my husband, our daughter and I could all make it to the passport office. When they apply for child's passports make sure they bring the child, passport applications filled out in black ink, two passport photos, original birth certificates with seal and a copy of birth certificate, minors social security card, if they have ever been issued a passport book or card before bring it even if its expired, and both parents need their Driver's license with a copy of front and back of the drivers licenses. At our visit to renew our daughters passport we also encountered a slight set back because I had just been required to renew my drivers license about a month prior. Our passport agent would not accept my drivers license as proof of ID because it needed to be 6 months old. Which was sort of weird since I have had a FL drivers license for over twenty years with the same number. We had to return home and come back with my passport and a photo copy of the page with my name, picture and passport number to complete the application. Oh, and we had to pay one part of the fee via a check and the other part could be a check or bank card but no credit cards. Basically, what I'm trying to point out is that even when organized there can be silly issues that require time so it is wise not to wait until the last minute to handle processing passports.
In addition, also know that your muster drill location may be in a different location for each cabin. If there were an actual emergency where you needed to evacuate the ship which ever child is assigned to each cabin/adult would be in the lifeboat with that adult. Finally, you may also want to discuss some sort of document for you to have permission to make medical decisions for minor children in the event that their Father is unable to since your out to sea or possibly out of the country and it may be difficult for their other parent to be reached to make such a decision if necessary.