Great job on covering the G-bodies.
I know you had some questions on some of the cars. Hopefully we can answer some of them.
The black 85 442- it appears the front bumper has been changed at some point. It looked to be chrome with clear parking lenses. ALL VIN 9 cars came with painted front/rear bumpers and amber parking lamps. It has correct style 442 decals on them.
The blue 87 442- Same for the decals. Correct for 87. Although the rear bumper emblem/decal SEEM a tad low from most I've seen. No big deal though, car looks excellent. The front bumper emblem originally was a single clear mylar decal with the 442 over the Oldsmobile all on one. A lot of times these start peeling on the edges (mine did) and I replaced it. Incorrectly as this one is too. The top of the 442 is right next to the bottom of the headlamp darn near with the "Oldsmobile" centered in the bumper. But GM replacement decals if you use the premask as a spacer puts it lower on the bumper. The gold pinstripe on the upper body break line, in my opinion only, is a bit overkill. But that's just my opinion which doesn't mean squat.
The burgundy 86 442- incorrect style for the period on the 442 lettering as you pointed out. The 442 emblem is on the correct side, but the Oldsmobile emblem is not. To each their own.
The blue 87 Brougham seems correct. The NP5 sport steering wheel was a Brougham separate option, so the steering wheel could be correct. The trunk was open, you can look for NP5 right on the SPID.
The first 84
H/O you came to there was a question of original paint. You started catching on when you got the next one. That's hard to determine on the video, but that orange peel stuff on the rear quarter isn't sloppy paint job but the lower body "rock guard" that the factory supplied. Correct repaints also have the rock guard redone if the owner really wanted the original look. Also, your vacuum tank probably looks like a half of an old style oil can over by the blower setup. That's probably because your car doesn't have cruise control from the factory.
Last but not least...here's how you work the Lightning Rods....