as you wanted it sooo bad, here it comes - videos in galleries!
For now, only Vertical gallery supports it 100%. The sly gallery has some responsive problems, on resize, that hope will be fixed in future versions. The rest of the galleries either technically can't support it, or there is no reason to implement video in them. If you feel one gallery closer to the "video" need, give us a beep!
2. You can re-arrange videos, exactly like using the images.
TIP: You can add iframe as well, or links from other sites than Youtube/Vimeo, supported by Wordpress. In this case, a basic icon will appear instead of the clip thumbnail. If you want to better divide video clips, attach videos to basic images. Either way, on the gallery, the image containing the video clip will be hidden (only on galleries that support videos).