This appears to be an enjoyable setting of Blake using period instruments. A wonderful effort.
I believe there is good evidence that Blake sang these songs although the tunes are not now known.

I have also seen reproductions of the pictures which accompanied these poems. I wonder if you could combine them with these wonderful songs.

Allen Ginsberg: vocal, piano, harmoniun; Cyril Caster: guitar, trumpet, French horn; Hanet Zeitz: flute; Bob Dorough: harpsichord, organ; Don Cherry: finger cymbal, harpsichord, trumpet, wood flute, Sleigh bells, beaded gourd; Peter Orlovsky: vocal; Jon Sholle: guitar, bass, drums; Herman Wright: bass.

tracks

Songs of Innocence
1. a) Introduction b) The Shepherd - 2:10
2. The Ecchoing Green - 1:22
3. The Lamb - 1:10
4. The Little Black Boy - 3:00
5. The Blossom - 1:22
6. The Chimney-Sweeper - 2:20
7. The Little Boy Lost - 1:06
8. a) The Little Boy Found b) Laughing Song - 1:24
9. Holy Thursday - 1:15
10. Night - 3:57

Songs of Experience
1. Introduction - 2:06
2. Nurses Song - 2:07
3. The Sick Rose - 1:35
4. Ah! Sun-Flower - 1:12
5. The Garden of Love - 1:02
6. London - 1:55
7. The Human Abstract - 2:30
8. To Tirzah - 1:42
9. The Grey Monk - 4:06

track credits:

Songs of Innocence
Introduction
Allen Ginsberg: vocal; Peter Orlovsky: vocal; Janet Zeitz: flute; Cyril Caster: guitar.
The Shepherd
Allen Ginsberg: vocal; Peter Orlovsky: vocal; Janet Zeitz: flute; Cyril Caster: guitar; Bob Dorough: piano.
The Ecchoing Green
Allen Ginsberg: vocal & finger cymbals; Herman Wright: bass; Bob Dorough: piano.
The Lamb
Allen Ginsberg: vocal; Peter Orlovsky: vocal; Janet Zeitz: flute; Cyril Caster: guitar.
The Little Black Boy
Allen Ginsberg: vocal, harmonium; Peter Orlovsky: vocal; Jon Sholle: guitar.
The Blossom
Allen Ginsberg: vocal; Janet Zeitz: flute; Bob Dorough: harpsichord; Don Cherry: finger cymbals; Herman Wright: bass.
The Chimney-Sweeper
Allen Ginsberg: vocal; Peter Orlovsky: vocal; Janet Zeitz: flute; Cyril Caster: guitar; Bob Dorough: piano.
The Little Boy Lost
Allen Ginsberg :vocal, piano; Bob Dorough: piano; Herman Wright: bass.
The Little Boy Found
Allen Ginsberg: vocal; Janet Zeitz: flute; Bob Dorough: piano; Herman Wright: bass.
Laughing Song
Allen Ginsberg: vocal; Cyril Caster: trumpet, French horn; Hanet Zeitz: flute; Bob Dorough: harpsichord; Don Cherry: Sleigh bells, beaded gourd; chorus: Allen Ginsberg, Don Cherry, Janet Zeitz, Cyril Cater, Bob Dorough, Michael Aldrich and Matt Hoffman.
Holy Thursday
Allen Ginsberg: vocal; Peter Orlovsky: vocal; Bob Dorough: organ; Don Cherry: trumpet, wood flute.
Night
Allen Ginsberg: vocal; Janet Zeitz: flute; Cyril Caster: trumpet; Bob Dorough: piano; Don Cherry: bass tom, beaded gourd, Sleigh bells, finger cymbals.

Songs of Experience
Introduction
Allen Ginsberg: vocal, harmonium; Peter Orlovsky: vocal.
Nurses Song
Allen Ginsberg: vocal; Peter Orlovsky: vocal; Jon Sholle: guitar; Herman Wright: bass.
The Sick Rose
Allen Ginsberg: vocal; Bob Dorough: organ; Jon Sholle: guitar.
Ah! Sun-Flower
Allen Ginsberg: vocal, harmonium; Peter Orlovsky: vocal; Jon Sholle: electric bass.
The Garden of Love
Allen Ginsberg :vocal; Jon Scholle: guitar, bass, drums.
London
Allen Ginsberg: vocal, harmonium; Jon Sholle: autoharp, electric bass.
The Human Abstract
Allen Ginsberg: vocal, harmonium.
To Tirzah
Allen Ginsberg: vocal; Janet Zeitz: flute; Cyril Caster: guitar; Bob Dorough: organ; Don Cherry: harpsichord.

I had been looking for a copy of this solely on hearing Ginsberg rendition of 'The Sick Rose' - his tremolo quite effectively conveys the emotion involved with Blake's poetry. Having not heard the rest of this album I'm really appreciative of the Internet Archive for providing a copy.

Question for anyone: is Ginsberg's voice being overdubbed or is that someone else (Orvlosky?) doing backup vocals?

First off - your archive is a wonderful thing!

I believe this recording is actually Allen Ginsberg's 1970 album of Blake songs, on which he was accompanied by Peter Orlovsky & others, and not a later Naropa performance of the Songs.