Where did Montage Mirror come from?

I am pleased with my "The Parade-Sunshine Girl: The Complete Recordings" CD that was released about a month ago. I am quite pleased indeed. I was only familiar with "Sunshine Girl" (of course), "A.C./D.C." (which had been compiled on one of the "Soft Sounds for Gentle People" discs), and "She Sleeps Alone" (which i found a slideshow video of on Youtube.)
It reinforced what I had a feeling about from these 3 tracks--the Parade was very talented and highly commercial without being completely derivative. It also verified that any song Murray MacLeod features on is golden. He has a voice that defies classification, sort of like a male Karen Carpenter (not trying to be sacriligeous but when he sings ballads he too sounds so damn heart wrenching.)
I would love to review the CD and ramble on about the deevolution of music. But my real intent in this post is to try to get some info on the bonus track "Montage Mirror." It is credited to Roger Nichols Trio (buy all their stuff.) It is written by Nichols and Roberds (Smokey of the Parade). There is no more info available. No producer listen, no year given. It was in the demo stage and apparently got no further than that.
My question is two-fold. Who is singing on "Montage Mirror" and why wasn't it put on the Small Circle of Friends (Complete) compilation. That even included that "St. Bernie the Sno Dog" song.
It doesn't sound like MacLeod is on the track as the mystery singer's voice is a bit lower and doesn't seem to have the same singing inflection in his voice. His sister isn't in it at all so she's out of the running. I've only heard Nichols' voice in recent years and it's much gruffer. Not saying his voice hasn't evolved in the last 30-40 years, but there is another factor that excludes Nichols from being the vocalist. He has a slower delivery than the singer on "Montage"; Nichols has more of a thought-out and reflective voice. But maybe I'm just overanalyzing. And besides, it bears little resemblence to any SCOF stuff as it has more of a garagey sound; more precisely it sounds like a song played in the background of an episode of Get Smart when Max shows up at a "counterculture party".
As to why it wasn't released on the SCOF, i'm still a bit baffled. I'd like to think the compilers just dug it up from a private owner who got it from a studio engineer or something. Those stories are awesome. To me it's more intriguing than all 3 Bourne movies. I have daydreams of stumbling upon a ratty cardboard box, with scribbles and stains and worn out masking tape on it and i open it up and i find a lost Monkees demo. Then I buy a reel to reel player and listen to it all by myself and never share it with anyone. Ain't I a stinker?
If any reader has any answers for me, it'd be appreciated. Or even if you have any cool stories to share about rare songs or Murray MacLeod or The Parade please do. I'm information starved.