Chris in Santa Cruz CA
My cousin, Holly, is Holly B.Lasal's suggestion looks like your best option for that many people. I've chartered trawlers, sail and taken my own boat up there a few times. Really enjoyed the area. I think a trawler is a great way to go with the very light and fickle wind. But it's not likely you will find a bareboat trawler to accommodate that many people.
Do you have a Waggoners guide? If not get one.
Some of my favorite memories involved:
Holly B's on Lopez
Riding a bike to the vineyard on Lopez
Walking to the school house on Stuart, is it still open?
So much to see and do, have fun.
The butter horns and cinnamon rolls are epic, especially if you love butter!