Mike Campbell is chiefly known for his superb guitar playing but he's an accomplished songwriter too: he co-wrote "Stop Draggin' My Heart Around" with Tom Petty and he's also a co-writer on several other key Petty songs (Refugee, Here Comes My Girl, A Woman In Love, You Got Lucky, and Jammin' Me which he wrote with Tom and Bob Dylan), he also wrote the music for Don Henley's "Boys of Summer".
Stevie Nicks was a guest vocalist on the 2006 Tom Petty & The Heartbreakers U.S. tour and typically performed that song in addition to "I Need To Know" and "Insider" with the band each night. If Mike is given a song on the tour it could be "I Need To Know" with Stevie singing as the other two were duets with Tom.
It's debatable and remains to be seen if the new additions to the band will be given a platform to perform their own compositions with the band. That said, deviations from Fleetwood Mac material are not unheard of in their set lists.
The last time Lindsey was replaced on the tour for Tango In The Night, Billy Burnette was performing one of his father's songs in the encore.
On the three occasions I've seen Fleetwood Mac they've performed Stevie's "Stand Back" every time, and they've also performed some Lindsey solo songs and at least one song from the Buckingham/Nicks album over the years.
But history suggests they will do "Go Your Own Way" and may dip into their pre-1975 era for the tracks Mick Fleetwood's statement hinted at from their "historic catalogue" to surprise the fans.
It would be fascinating hearing one of Neil's songs given the full Fleetwood Mac treatment, and a Tom Petty & The Heartbreakers song for that matter - and I hope it happens, but they may play it safe given that Lindsey's absence is already a big ask of their fan base.
Opening night of this tour will be fascinating.