Hopefully if anyone searches for help with this, they get to this post first.
I made an important discovery after posting part 1.
By renaming my videos, the ones I wanted to keep on the iPod aren’t there. It says they are there in the finder window, but when I went to play them on the iPod, they are not there. Foiled again. It’s looking like in order to keep videos on the iPod, they have to keep the stupid 0000.mp4 name. Either that or else renaming the dat file did it. I need to do some more testing. But I wanted to post this in case anyone comes looking. Don’t rename the files on the iPod if you want them to stay there. I would copy the un-named file to the desktop or wherever and then re-name.
I’ll check out the dat file stuff and post another update.