Wow - you are after what many consider to the Holy Grail of photography!
It's great that you wish to "develop a style/look" of your own and while it can come as a result of pushing buttons and sliders in Lightroom, there is much more to it. A unique visual style develops from months and years of shooting, not post-processing. Even post-capture style develops out of what you learn about your own images and their content and not from a specific tutorial. While there are presets you can use, if they are commonly available then how unique are they?
It is helpful to consider that standardizing "the look across all my final images" may, in fact, be counterproductive in that each photograph and setting may require its own lighting and composition and treatment in Lightroom. In other words, rather than all the photographs having a similar "look", you might consider tailoring the "look" to the content of the image and what you as an artist wish to portray. The links you provided show this concept quite well. Many of the photos from a single collection have a similar look, but that look changes with the setting and content of the photographs. What "look" looks best is as different as the photographers who make the original photographs, the settings and lighting they choose and their personal vision.
For example, having the same white balance under a variety of lighting conditions may not properly convey the nature of the situation in which you were photographing. If it's really important to you then carry a white balance card (white card) with you and shoot the first photo with the card in the photo so you can "zero" the white balance to it. All the succeeding shots should have a similar white balance provided the lighting hasn't changed and can then be synchronized in LR. But using a white card in itself may be counterproductive, as you may lose the spontaneity you want to achieve in social documentary photography.
The best advice I can give regarding Lightroom is to practice, practice and practice to develop a workflow then stick to it while still being open to the variables presented by each image. In the LR3 Develop Module start in the Basic palette and work your way down. My preferred order is E - R - B - FL (Exposure - Recovery - Blacks - Fill Light) but, if I have slightly clipped highlights (from Expose to the Right metering) then I will Recover them first then move to Exposure. I rarely need to use Brightness, Contrast or even Tone Curves. That being said, don't get too comfortable with LR3 as LR4 has a different, and, to my way of working, superior workflow with much better Tone Mapping controls in the Exposure - Contrast - Highlights - Shadows - Whites and Blacks.
I'm sorry if what I've written isn't entirely helpful, but you have asked for some specific tutoring on a subject that for many photographers is a life-long pursuit. Hopefully, at least, this gives you a starting point.