I bet the sticking point with Mick is that if Lindsey didn't want CM songs on SYW, then they wouldn't be, he (LB) would get his way because MF feels he NEEDS to keep SN/LB on his good side. THEY run the band now in effect.
If LB was NOT interfering in that decision, then I can't see Mick turning down CM material for SYW as that would be a "true" Rumours lineup album (his wet dream) hence more money.
I don't think he would care if people went to SYW tour shows expecting to see CM there and then saying "hey, where is she? she's not here?" He'll get money off of that ticket sale anyways (whether they were happy with the show or not). Whatever way he can make the most money is what Mick cares about.
I wouldn't like to think that LB has this "I need to respect them enough before they make a guest appearance at a show" type of attitude but he probably does though, who knows. JMHO though.
John