Ok this is very strange now.
After four tries, I found a video clip that would animate on this third plane object as a texture. But I needed to trim a few seconds off the beginning of the clip so it would be at the right place for display. It is an .mov file 1280 x 720 just like the other clips that are working.
Just for data, working clip #1 is 11 seconds, working clip #2 is 8 seconds and working clip #3 was 9 seconds until I trimmed it down to 7 seconds by taking out its first two seconds. I did the trimming with QuickPlayer and saved it in the exact same format it started in. After trimming working clip #3, it no longer works. It will only display a static image. This is beyond frustrating. Every other variable or setting I can find is the same between these clips. What is going on?