I think we can all agree that the details of our plan will have to change depending on how much they know. And we don't have time to flesh out the details right now.
We do agree that our plan is to pretend to sell some of the elves in our party, so we can find out where their base of operations is, and get someone on the inside. Then the rest of us will provide a distraction while our people break the elves out.
I don't plan on agreeing to anything up front, neither should anyone else. We send our two people to the meeting, and they avoid saying as much as possible while trying to learn as much as they can. Once we know more, we figure out the details.