I do believe all three hotels will allow 5 persons in their standard 2 Queen rooms. (I definitely know the Royal Pacific does as I always tell them I have 5 persons in the room so I can get 5 room keys. Note that the room keys are your Front of the Line access ticket throughout the parks.)

The rooms at the Portofino will generally be the largest of the three onsite hotels, but it will also tend to be the most expensive. The Royal Pacific is the least expensive of the 3 onsite hotels, but the rooms are also the smallest.