We were in the Family 2 bedroom Haven suite on the NCL Pearl to Alaska! It was great to view the glaciers from the private Haven deck. No crowds whatsoever!
The 2 bedroom Haven suite does have 2 separate sleeping areas and 2 separate bathrooms. I would book that category for the master bath alone! The shower and bathtub have windows facing out and have the BEST views. I think that bathroom is bigger than most cabins. You should look at video tours of the cabin and bathroom on YouTube.
I am not sure that the beds in the "master bedroom" separate as it is literally just an alcove next to the master bath. So, the most important question would be, will you be able to share a bed with your Mom?
There is plenty of room for 2 young adults in the second bedroom with en suite bath which is about the size of a regular cabin bathroom.
Personally, our family likes to hang out together. Even when we booked 2 inside cabins (one and done), my girls would come over and squeeze into our cabin to chat, etc. So, the communal living room in the 2 bedroom was perfect for how our family like to vacation together.
Now if you or your adult children need space apart from each other, 2 separate cabins may be better for family harmony. I probably would not want to share any of my private space with my in-laws for an extended period of time for example. Meeting up for meals and excursions would be enough together time with them.
You know your family better.
But in terms of separate sleeping spaces and 2 bathrooms, the Family 2 Bedroom Haven suite has both but they are not equal at all in size and "luxury." If I were paying for the trip, I would prefer the Haven 2-bedroom and the master bed and bath would be MINE!
Good luck!