#3
Scream maniacally until your vocal cords get shredded enough to sound like this. Also see: The Hives
Tickle me.
#4
Well, this is obviously simply pushing your voice to the limits. Notice how he can't stay on one voicing? If you want to do serious Screaming (or Shouting, where you sound like you are pissed on the neighbour's kid, see Rob Dukes from Exodus) you must do it slowly. First try to simply yell at some imaginary person, (I suggest not to yell at actual people :P) try not to push your voice to the limits, stay right behind that limit so you can maintain one smooth long Shout. (First Try Simple "HEY"s). Push air from your abdomen, not your chest. Try to breathe into your stomach (Your chest will pump up since your Lungs are there, but focus on your Abdomen) and then use that air. You well become used to it where you don't think about it any more.
When it starts to hurt, examine what went wrong and try a way without pain. If you can't find out, stop and give your vocal chords a rest. Don't force, relax.
Ever wondered why so many screamers get red heads? It's ****ing exhausting!! You shall stay relaxed, but you still have to limit the Air-Flow with your False Chords (Above the Vocal Chords). It's no forcing, rather like lifting a weight. You can remain relaxed while concentrating your power on the needed muscles.
Never practise quietly, because it's a different feeling but never push to the limits. Once you've got your personal technique, you can apply more pressure, since you know when it starts to hurt.
Don't expect to learn it in a couple of weeks. I needed more than a year to get to my point.
Do not mimick a scream, since you will hurt your Voice. I always tried to growl like Johan Hegg from Amon Amarth, but since I stopped mimicking it works fine.

#5
if i was you i honestly would attempt to scream like this because it can ruin your voice but if you really do wanna scream like that then you need to take voice lessons and learn how to scream correctly to avoid any harm to your vocal cords