CD/DVD Combos?

You don't get any disks at all when you purchase from the iTunes Music Store - it's only a download service - so I'm confused as to what you're referring to.

No, as far as I can tell, you do not get the video tracks as well, just the audio. The CD/DVD Combo reference is part of the album title, it would appear; the DVD part apparently only comes with the physical version (which is probably why it's half the price on the iTMS, since you only get half the material).