#2
Good quality cover of a great song. You seem to be straining a bit, which doesn't seem fun.
#3
Don't want to be an ass, but the vocals sound over-processed (too much overdrive/distortion), specially for a cover, I can't really give you any tips on improving your vocals because of this.
#4
little bit of parallel Drive and a notch around 12K to kill a nasty overtone, and I mostly used the overdrive to clean up inconsistencies because it was one single take.

More of a showcase of the mix than the actual vocals, or i wouldve done the video in my bedroom screaming into a TV remote while the song blasts out of a Stereo.

Its very rare to hear any dirty vocals without processing these days.

Edit: not really straining, although i do tend to get red in the face from the overall pressure, it never hurts or anything like that.