While Bruce did a really nice job cleaning up the harmonies (maybe making them a little too slick at times) on L.A. (Light Album), I don't hear a lot of individual Beach Boys' voices on some of the tracks. On "Baby Blue" I just hear Dennis and Carl, on Carl's tracks, "Full Sail" and "Goin' South", I don't hear many/any other Beach Boys; same with "Love Surrounds Me" and even "Shortenin' Bread" (just Dennis and Carl).
I asked in an earlier post and am really curious. Is Brian Wilson on "Sail On Sailor"?
The bulk of the backups on "Baby Blue" are Bruce and Carl, with Dennis of course.
"Full Sail", Bruce and Carl, Geoffrey Cushing-Murray, and possibly Dennis.
"Goin' South", Bruce and Carl, possibly Dennis (or someone other than Mike) on bass.
IIRC a contemporary interview suggests it's all Bruce and Carl on "Sumahama."
You may be right about just Dennis and Carl (and Christine McVie or another female singer whose name I do not remember) on "Love Surrounds Me."
Dennis, Carl and Bruce for sure on "Shortenin' Bread." I think Al may be on that one, but I can't prove it aurally.
Not ruling out cameos by other members on a part here and there, but my point is, with the possible exception of "Love Surrounds Me," Bruce is on all the tracks you mentioned.
I don't believe Brian is on "Sail On Sailor" at all but C-Man could tell you for sure.