The Ugnaughts are supposed to be from the nearby Anoat system if I remember the old EU correctly. I always thought they were saying "The No-Add system" until I turned on the dvd subtitles.

Anyway, McQuarrie's floating islands of moss with their humanoid inhabitants flying around on thrantas is something I could see being added into the background of the Bespin arrival (before we actually see Cloud City) or just added editorially like they did with the cloud car that flies past Leia's room.

It was probably a stretch in '97 when all they could do was add the refinery, another McQuarrie concept, into the foreground of one of the shots. But now that we're in a post-Avatar world, showing the native lifeforms of Bespin would certainly be possible.