Other mistake: One visual that has always bothered me that I could not find in your list were the scenes when the mother ship first appears. It's enormous scale appears to dwarf Devil's Tower and the whole surrounding area actually, but when it moves over to the "landing strip" area and begins to rotate 180° (right-side up?), it suddenly seems to shrink to a much smaller size and mass during the slow revolution. On its originally-seen scale above/behind the tower, one would think that either the great ship's outer prongs would have been torn off, or more likely the impromptu landing site and most of Devil's Tower would have been destroyed as the huge craft rotated itself. The visual scales just do not stay consistent throughout the film's climactic final act.
Continuity mistake: When the blonde girl is persuaded to talk to the Trogladyte, in different shots, her hair is either over her shoulders, or off her shoulders.
Revealing mistake: At one point in the movie, dumptrucks are sent in to contain the Mighty Peking Man. You can tell that these, like most of the movie are toys.
Factual error: In the scene where a politician is making a televised speech away from the studio, the camera is a vintage RCA black and white TK-12, but the camera monitors in the van are all in colour.
Visible crew/equipment: During the opening scene when the boat is being pushed ashore you can see the shadow of the boom mike in the water's edge.
Continuity mistake: When Evel Knievel goes to the insane asylum to break his buddy Will out of the institution, he crashes through the front door with the Stratocycle, breaking off the airplane-style wings on each side of the bike in the doorway. In the next shot, as he rides down the hall, the wings are still intact.
Continuity mistake: In the opening scenes, when David is chiding Gail for grabbing him through the porthole of the wreck, his right hand is gloved, then ungloved, then regloved..all in the space of a few moments.
Revealing mistake: Near the end of the film, the mayor, played by Jim Backus, is speaking to Elliot the dragon, who is invisible. The mayor has a cigar in his mouth and smashes it when he turns to greet Elliot. The scene is accomplished by having Backus turn and smash the cigar into a large pane of glass. However, the reflections on the glass are visible.