The OKW villas have two separate sinks in the bath areas (1 by the shower/toilet, and one outside by the jacuzzi.) Thus you'd have 3 total when you include the 2nd b/r. BCV units would only have 2 total.
This is incorrect. The BCV MBR/ bath area has 2 sinks, one by the tub, the other in the shower area. Plus, the toilet is a separate room behind another door, which is nice. You'll have a 3rd sink in the lock-off.
Since you booked through CRO you won't get the 2nd bed, maybe you'll want to bring an air mattress as a back-up for one person. A lock-off might actually be a nice option, giving the 4 people in the studio an extra sink/microwave/coffee area (if they're up early they won't disturb the people the 2 people asleep on the sofa bed in the living room). You'll also have that extra sink to use, bringing your sink total up to 4.
I agree that the 2 b/r is going to give you all more space than 2 studios or regular rooms, plus the w/d, etc. People may come and go at different times (a benefit to being within walking distance of MGM and Epcot!) which helps. Give some thought to who goes to bed early and who rises early and place them so it makes sense.
Good luck! We did a group of 8 last May, including my 18 yr. old dd and her 3 friends in the studio portion and it worked out fine. I'm sure you'll have a wonderful trip.
