I can confirm that the displays on both of those screens are the same. Check the data sheet if you have any doubts
The second one comes with a drive board, which is important. You need the drive board to power the LCD and convert video signal to a signal that's usable by the LCD
Also, keep in mind the resolution of the display. The 2 you listed are both 800x480, while the eBay one is 480x234
The Wii and GameCube output 640x480, interlaced for composite, and interlaced or progressive for component.
If you are going for composite 480i, I recommend getting an inexpensive display similar to the eBay one, but one that is 480x800, or 480p. (Some 234x480s are labeled as 480p! Watch out, and be sure to read descriptions)
For 480p on GameCube, VGA modded component cable is the way to go, and buydisplay is a good choice.
As for 480p on Wii, I do not recommend going through VGA. VGA converter chips tend to be problematic and wash out the color. Get a buydisplay LCD with HDMI in, and run it through a wii2hdmi. This will provide better quality video, and won't give you problems with games that don't support progressive