I know this is a crazy idea, but I think it would be cool if we could make a special vandals category under all the people who have vandalized this wiki If not, i completely understand why that would be so hard.
1. The "artist" in the infobox refers to the person who wrote/created the song
2. Yes, you can add videos from Youtube and place them on the page or infobox. When it comes to the page, however, after uploading it, first make it a gallery by doing going to source mode and make a new section called Videos and add: < gallery ></ gallery > (Of course without the spaces). Once that is done and the video added, remove the [[File:]] part (that includes the brackets, just leave the title of the video). If you want to add the video to the infoxbox, choose the Music infobox, and scroll down until you find "Video", then add the FILE of the video, not the link to it and you should be good.
N.B. While it is not against the rules to upload videos, please ONLY post high quality videos (aka, no potato quality videos) and no episode clips other than sneak peeks are allowed.