As an idea for the new lineup ... putting out something like a three song EP might cool off some of the animosity and drum up much needed support for the upcoming tour.
Perhaps the EP could include one Christine song, one Stevie song, and one Neil Finn song. I'm not sure if Christine and Stevie have extra songs lying around but Neil is the type who has dozens of unreleased quality songs.
I know of five Neil songs, off the top of my head, which have never been released on a Neil Finn project and are pasted below. Any of these songs could easily be reworked by the band to sound like a classic Fleetwood Mac song.
1. Serious in Love
https://www.youtube.com/watch?v=aw7M....be&t=1h11m48s
2. Guiding Star
3. Ray of Hope
4. Love Is All That Remains
5. Blue Hotel