1)
yes, download wiitdb.xml
Settings > Update > wiitdb.xml
it could be named "gametdb" instead. it's "wii title database from gametdb.com website"
then, you can take advantage of that title database by doing this :
Settings > Features > Use wiitdb : Enabled
2)
I'm not sure to understand.
there could be different cause or reason why you get this.
1. you can download game covers by pressing 1 (or 2) on the wiimote.
2. banner animation are not available for gamecube games, and you need to download them (same than the covers, press 1 or 2 no wiimote) to get a custom made animated banner.
3. the banner animation is not always displayed, it depends which "visual mode" you select.
Settings > GUI > game window
rotating disc : you see the disc image for all games
banner : you see the banner for all games
banner on banner layout : you see the animated banners ONLY on the banner layout, the other layouts are displaying the rotating disc.
If you are on banner layout, using banner game window but still can't see your game's animated banner it means your game is corrupted.
find or dump a new ISO.