As far as I know the only on-site hotel that you could have 5 adults in would be the Davy Crocket Ranch, all of the others are a maximum of 4 adults in one room.
We stayed in a family room on the Admiral's floor of the Newport Bay last year. We "imagined" that it would be a larger room split into two with an interconnecting door...
...we imagined wrong!
A family room is one large room with two double beds and a convertible sofa.
So, when my wife, DS1 (5y), DS2 (18m) and my parents arrived in the room we were in for a bit of a shock
Fortunately, we all get on very well, but there is no privacy!
Travelling to the Sequioa tomorrow ... and we have two rooms booked!!
Explorers is a really good option as there is a double bed and 2 singles and then you can add an adjoining room which has a set of bunkbeds making it into a room for 6
The Explorers is very nice - we stayed there in February - I'm not sure if 2 adults would want the bunk beds though. It's like a regular hotel room PLUS a second small room with bunks in it. We stayed recently in Citea Magny le Hongre and we loved it. I did a review of it here. I think as it's all adults, I would go for that. You'd have so much more space. You could book the 3 bedroom villa which accommodates 8. We had the 2 bedroom one so I'm guessing the 3 bed villa has an extra double bed at least. It's a nice area. Good luck in your decision.