No problem with advisor in solo tents. Kids have to be paired unless odd number. I used an MSR Zoid 2 last year, and it had plenty of room solo, but comes in at over 4 lbs.
I'm getting a Tarptent Contrail today! 23 Ozs.
Also, I would be a bit concerned about 2 - 2 qt pots for a vrew of 12. We had 2 - 4 Qt pots, and came a little close on some meals.
Getting out of base camp with 35 lbs including food, water and crew gear is pretty hard to do. Not impossible, but you really have to work at it. That's my goal next year. I have the Contrail, Golite odyssey, and a Big Agnes Zirkel bag which saves over 7 lbs from last years hike.
Last year was my first trip, and I now know what can be left behind, like a camp stool, too many batteries, less socks and shirts.
2007 710-O2 Trek 14.