I love that sketch. I bought the Richard Pryor Show on DVD just to get that.
Yeah, there is more than one patron wearing a POTA costume. Those were probably borrowed/rented from Fox’s costume dept.
A lot of the Cantina Aliens were only partial creations for the insert shots in Star Wars. Even Muftak is wearing pants here, as the original suit ended below the waist.
I’m betting the tentacle monster came from a Sid and Marty Kroftt tv show like The Lost Saucer, or Far Out Space Nuts (both 1975), which interestingly enough was shooting a alien bar scene on the Fox lot when George visited the set! It sucks that it’s never been released on DVD.

I’ve racked my brains for years trying to recall what I think was a one off tv special, that had an even larger grouping of the Cantina guys, plus what looked like the suit from Alien! That would place it around late 1979 or early 1980.