I don't really know much about the rules for how many are allowed in the rooms. There seems to be a lot of different information (and I have never asked directly since our family is made up of 4 and all the units have worked for us).
If you go with a 1 bedroom, then you may want to get an inflatable bed. That way everyone will have a place to sleep.
You may want to look into 2 studios instead of a 2 bedroom is you want to save on points. The 2 bedroom units are very nice though. We had one at HH (only unit that was available) for our family of 4 and we just LOVED it. I wish we could afford more points so we could always have the larger units!
You could also look at the points for the FW Cabins. That is what we are going to do in December when my sister comes with us (making us a party of 5). We really want to try out the cabins too, so it works out. We camped there once in a tent and the kids just loved the campfire program at night (which is free) and they have bike trails and well.....it is just beautiful over there!
Anyway, just some thoughts. We also considered using our points at the PO resort since they have a trundle bed that allows you to sleep 5 in a room (and maybe 6 with a crib, I'm not sure, you would have to ask). The PO option is less points than the FW cabins, but we thought it would be nicer to have my sister in a seperate area (living room murphy bed). The cabins only have 1 bathroom though, the the 2 bedroom units do have 2 bathrooms.
Good Luck!
DJ