I would absolutely rate that first video as E. There's nothing in that video that I wouldn't show my 5 year old and they would get upset or bothered by. There's no way any child would understand that's a reference to something and even if it was I don't see where it would be bad for them to see it.
As for the copyrighted music I tried to look up if he had permission or if that was free source material, but couldn't find any results. I can't give you an answer about that.
Oddlem
I think for ratings, the mods typically only take action if it's adult material (like straight-up hardcore NSFW in an E rated thing). I don't know specifically if I'm right or wrong, but that's what I think is the case.
With the copyright music, I also think reporting correctly doesn't do as much as reporting incorrectly.