The set-ups are a little different.
2 br lockoff is a studio + a 1 br with an adjoining door, 2 bathrooms total. The studio portion will have its own entrance to the hallway, a kitchenette, a queen bed (I think), and a pull out sofa. The 1 br portion has a king bed, a living room with a pull out sofa and a murphy bed under the TV, a full kitchen.
The dedicated 2 br has one room with 2 queen beds, 1 room with a king bed, a living room with a pull out sofa. There is one entrance to the hallway for the entire unit, 1 full kitchen, and an extra half bathroom for 2.5 bathrooms total.
If the rest of the group has hopes of sleeping in later than the baby, then the lock-off might be a good option and put the couple with the baby in the studio portion. They can warm up some food in the kitchenette and slip out their own entrance if they want. I will tell you that the adjoining doors are still not perfect at blocking sound. When our twins were 2.5, one fell off the eating bench right near the adjoining door (of which we did not know the occupants) and screamed at like 6:00am. Pretty soon they were knocking on our door... So embarassing. Anyway, this leaves probably you two in the bed in the bedroom and your son and stepdaughter in the living room.