Not an answer to your question but you can find another recording of the same song done by Lehua Kaapana Nash (Ledward's sister) on a cassette she did back in 1996 called "Ki Ho'alu Kaapana Style". Just in case you want to compare versions.
"The music of the Hawaiians, the most fascinating in the world, is still in my ears and haunts me sleeping and waking." Mark Twain
Yes, I remember some statements from Barry on the subject. They were not quite done with the first Hapa Album and were looking for more material. Barry stated that Justin's Lullabye was a slowed-down and slightly rhythm adjusted version of Kaopuiki Aloha (and without the Steven Stills accompaniment). I remember that Barry indicated that it was a "throw-away" filler tune and was very surprised that it became as popular as it was. At the time KKSF (the light jazz station here in SF) was featuring it heavily (1992 or 1993). I believe Justin was his son. (and Kaopuiki was the bass player on the "Hapa" disc).