>>/7096/
First one is by Tridashie right? Second one I haven't heard before but is pretty cathcy with AJ. Third one it seems like a can recall. Like it was done by a artist who did this awesome castlevania theme in a similar fashion. 

> I had never heard this style before pony music-videos started gaining steam.
I honestly want to do research this. For this is something I could totally believe with all those who started out as YTP editors. 

> I grant you, the last two are covers, if you will, of existing songs, 
Is AJ's always true not a cover? That's the only one I don't recognize though its in the middle. 

> but I think the description holds true even I can't easily find further examples in my MP3 directory right now.
Here is my go to that I have posted before a couple of times.