accomplishing this is going to be a major feat. again. i admire your optimism. my pessimism tells me that there are a lot of ways this can go wrong.
the big risk is that mozilla won't go out with a bang. they will stick around and even without funding try to hold the reigns. that will make it hard for other organizations to step in. while many have a vested interest in keeping firefox alive they may want to get a seat at the table.
(i am just making this up as i go, so don't take it to serious, but i just had a thought of what ideally might happen:)
when mozilla loses its funding from google they realize that in order to continue there needs to be an organization that is comprised of all the above organizations that want to support an open internet. they get together to form some kind of super organization like a consortium where they all are a member of and all contribute to the continued funding of firefox.