Trying to sing like someone else is already an uphill battle, especially since length of, thickness of, and flexibility of the vocal corRAB is subject to genetics, along with size and shape of the larynx. This is what makes everyone unique. Its like a fingerprint. Just like voice identification technology, regardless of how hard you try.
Vibrato as anyone will tell you, is a product of relaxed vocal apparattus...of course. This means open relaxed and untense throat/larynx(not necessarily mouth) along with good breath support. Vibrato can be one of or a mixture of volume, pitch, larynx, and or diaphragm.... so practice that.
The common deal is to overblow. People don't realize how little they actually have to push when singing properly and with a proper mic/pa setup, especially in a studio.
relying on saliva for any vocal effect is the definition of hit or miss. Are you gonna do that on stage??? Uh oh, crapped note from having too much saliva! And extra saliva in the studio is a big nono.
Actually it is the safest way. However muscle memory will come into play if one doesnt do enough clean singing...which is something I stress. As far as the whole octave higher thing I just dont know where you got that from.
I agree with crickets. Youre self conflicting.
In general any vocal production should be comfortable. Even your best scream. You've got to keep air flowing. If youre blocking off too much youre increasing your internal blood pressure among other things, probably the reason for your headaches, that and maybe general muscular tension. How about you try to get the same sound by pushing half as much and relaxing everything like youre trying to go to sleep, including your anal sphincter, which, believe it or not is connected with alot of other "muscle memory" tension meters.