Hi, Laura. I'll stay out of the main discussion here, but I just wanted to address one point as a bystander who has spent a lot of years involved with Internet startups:
Laura Hale wrote:
[...] There are other places we would like to approach. (And if you have ideas for who would be a good fit, please get in touch with me.) Is it ethical for us to approach other people and organizations while we have this on the table with the WMF? If we approach other people in the mean time, does that signal that our interest in the WMF is dead?
What you're talking about doesn't have a lot of direct precedents that I know of, but with business acquisitions it's common to talk to multiple people at the same time. Indeed, in some cases, I understand it's a legal duty to do so. The notion is that the fairest deals happen in the broadest markets.
In that context, the way that one signals interest is to continue to talk, and by the amount of effort put into the talking.
No matter who you're talking with, one concept you should be aware of as you go forward is what I've heard called "the venture capitalist's no". Because things on the Internet change with some frequency, and because the future is hard to predict, there's often not much incentive to give a clear negative answer. There's also not a lot of incentive for demanding them; as satisfying as clarity is, startups find it more valuable still to keep their options open.
I'm not sure how much that applies to the people you plan to approach, but if I were you I'd try to be prepared for a fair-bit of well-meant fog.
William