Hi,
(A bit long and possibly winded for some folks here, btw)
Watched the videos and ... boy ... it's no different than working with an actor and again one of the reasons why a lot of rock music is not as good as many other things ... the ability to have someone else with you, that is outside you that can help smooth things out.
It's generally thought that most music is a "learned" process and you follow the learned path with the proper exercises to be able to eventually define yourself.
In reality, rock music in the 20th century, has busted a lot of this stuff to smithreens and created something else that classical music is still trying to define how to interpret and until they do, a lot of the rock music singers and personas will not be considered good/great singers.
This is really tough area, and one where you have to make a call ... do you just be another baritone and do what everyone else has done, or do you take the step of doing this with ... let's say ... a rock band ... or a jazz band ... so you can create a massive hybrid that will throw people off ... which has one massive advantage ... they can not compare it to the "book" (or scale/staff) ... and it helps define you.
There is one massive example of some of this style of singing and it will be found in the group "Magma" and it is insane, specially when he writes this whole stuff in a different language and it is sung by anywhere from 3 to 5 people, including his wife Stella. It is, an insane repertoire, and when you listen to ... let's say Khontarkohz or Udu Wudu... you're going to sit there totally confused and go ... wow ... where did that come from.
That style of singing has its roots in that Germanic tradition ... but you won't exactly find it readily. I believe there was a French singer named Catherine Ribeiro that also did this with the woman's voice and a rock band ... to a very different idea and concept in the late 70's and early 80's, again, the main issue is ... that radio stuff (pop music) can not handle this kind of seriously defined music and how it is used.
I'm a believer that ... if you have to match your vocal identity to the music, then the music is not good enough ... and this has hurt Opera tremendously in the past 50 years to the point that no one goes to see one anymore, and we laugh when we discuss Tommy or The Wall as Rock Operas. Basically, the moods, the attitudes, and the explosion of emotion would be what is more needed in opera to match the time and place, and yet, it is often left behind.
As a director, I tend to work along the lines of smoothing out all spots that are not clean, or clear ... so that your transitions get easier to work on ... and to do this within the context of the Austrian famous competition, is difficult, and I would only do it if they allowed me to play my own piece of rock music, otherwise you are just another piece of the wallpaper of the "idea" of what that music was all about.
There is a lot of this stuff that ended up in Kurt Weill and Bertold Brecht's work, though, the link is probably more distant and some music professors might not like the idea that these two folks had to take the music out of the hands of the impresarios and rich people that thought they "were" what music was about. Eventually, with rock music, this is what the 20th century is all about in music.
This is not "voice teaching" or "helping" for you, but hopefully you can at least make a call as to how you want to use it ... because I doubt that anyone is going to pay several bucks these days to go listen to someone sing some Lieders at your local university. The majority of folks will go ... nahhh ... American Idol is on!
And that's how a lot of music is wasted! However, I do not think that some of these were exactly a style as much as it was a feeling by some of those folks and how they used their voice ... which ended up with a "style" ... years later. This is how I see it ...
Other listens? ... Klaus Schulze ... not sure it is Black Dance or one of his early albums had one singer doing this along side the electronics ... it was really nice, and I often think of it as ... that guy is singing in the shower! Crazy, isn't it? But it is superlative, but not something that most folks in this board will likely have heard or studied.