1) this was a photoshoot done at the recording studio while recording the 1975 album, probably in February. A different version was published last year in the Rumours re-issue:
http://i.imgur.com/pehxeRR.jpg
2) this is interesting, a very similar photo and no doubt it's from the same shoot, was published (in Life magazine I think? but not sure about that) in april 1976:
http://i.imgur.com/0QrbgAg.jpg it can also be found on the Getty Images website:
http://www.gettyimages.nl/detail/nie...fotos/50376297 but it's attributed to a photographed named Jullian Wasser, so no idea how it became part of Herbie's estate?
3) never seen this block puzzle concept before but the photos seem to be from that first February '75 photoshoot.
4) yes with Stevie's parents in 1976, very cute photo.
6) I have no idea who those people are I don't think I've ever seen them in other photos, but I'm fairly sure the photos were taken backstage at the Day On The Green festival in Oakland, CA on april 25, 1976 because Christine is wearing the exact same outfit:
http://i.imgur.com/WFmJZTA.jpg
I have no idea who the couple with Mick is or who the girl with Christine and Stevie is!