Plenair is the girl that takes care of the dark assembly in disgaea ds, you can recruit her after you've cleared the game once (any ending easiest one to get is lose to vyers in ch 2 or 3) by selecting the "blank" option below tutorial. Shes a good character but voiceless so shes kind of dull to use. My best character in that game is my level 9999 Bastet (Rank 6 Nekomata). I beat that game to death I love it.
Well regarding your self-protrat is it supposed to be abstract or realism, If its abstract you can draw yourself in the form of your favorite animal, a sphinx, or perhaps a greek god. (with the leaf crown). As far as old man goes you can draw a typlosion walking through flames like sephiroth did in his infamous fire moment. And your sig you should make a plenair and usagi sig because she is effing adorable. Just google search Plenair shes the girl with blue hair and white dress with the zombie rabbit plushy. Hope that helps. :3
Oh wow. Yeah, I really like these, especially the newer ones. I can see there's a big improvement in text. And these really use brushes/effects effectively, drawing attention to the subject instead of obscuring it. Your progression of signatures really shows how much you've improved.
I'm not the best person to ask about the specifics of vector art because me and the pen tool are old enemies. I do stuff that's sorta copy-cat of the vector art look occasionally, but not the real deal. So here's the handy-dandy Wikipedia article: http://en.wikipedia.org/wiki/Vector_graphics
In the context of anime/manga, vector art usually shows up as redrawn images of scans/screenshots that are higher quality, using layered shapes.