We stayed in a lake view GV this past March. There were only 8 of us as another family canceled at the last minute. That being said, we went from 12 to 8 and that worked out great. The are plenty of beds but there isn't as much privacy as you would think. The two story layout especially at BLT lends itself to lots of noise reverberations. The common area between the bedrooms upstairs had a pullout couch but whoever sleeps there will need to share a bathroom in one of the bedrooms. The downstairs has an extra bathroom that is really nice but there isn't any privacy. The table and kitchen are great- very roomy and fun to have a sit down meal in one place. IMO, we were good with 8 (4 adults, 4 girls) in the GV but it would have been surprisingly tight if we had 12. In your case, you may want to consider other options but keep in mind that the studios are really cramped.
All in all, it was fun to stay in a GV as the two story windows and views were awesome. Since all the kids in your crowd are girls, I would plan on the GV and enjoy it for what it is.