The 1BR suites at BWI are the Garden Suites which are like lofts--the bedroom is upstairs and is open space overlooking the downstairs living room; it also has a mini kitchen (sink, small refrig) and its own small backyard with garden. However, those are really only for four as it has only a king bed and a pull out sofa queen. There are also two bedroom suites which start at over $1,000 a night. You could instead get two connecting regular rooms.
The villas have 1BR villas that sleep 4 and 2BR's that hold eight; thus you have the same space issue there as you would need a 2BR. The 2BR villa (regular rate is more than Garden Suite but a lot less than 2BR suites at BWI) would be ideal as it has a lot of space and you don't need to use the kitchen (it is still great to have the refrigerator to keep drinks cold).