In his March 2017 newsletter, Hardy Fox says :
Much like The Residents, the Delta Nudes never existed. It was a loose assortment of people who got together and made noise, and never bothered with a name. The name was added only recently out of needing a convenient way to designate the time period.
But found in that group were the people who were to become The Residents, the man who would later become Snakefinger, and a handful of other regulars :
The Fifth Resident
The Residents tackled making a movie with great energy. At the time music was still thought of as a side thing. Everyone's friends and their friends were involved in the four years of sporadic production before the project finally died, undone by technology and personal growth.
The people who emerged unscathed from The Delta Nudes period included one extra person, not just the four one normally hears about. That is because the fifth guy didn't last too long. You can see him in the Vileness Fats footage though, lumbering along as half the Berry Boy Twins, Arf & Omega*
That would be Palmer Eiland. A brilliant guy with a soldering iron, but San Francisco was proving too much for him, and he had to bow out and go back to the South. He pretty much disappeared, too. I talked to him on the phone a few years ago and he promised to give me a full explanation on what actually drove him out of California. He won't ever do it though. I'm okay with that. If he had been approached by The Theory of Obscurity film makers, he would have refused to appear in the film.
* After Palmer left, a couple of different people stepped into the role. If you look closely, the person in the costume can change even within a scene.