范儿 originally referred to the poses, set-pieces, and songs that opera performers (maybe just Peking Opera performers?) were supposed to be able to hit -- sort of like "marks" in the expression "hitting one's marks." (At least, this is how the term was explained to me.) These days, though, it's basically just "style" or "look" (as in "going for the heroin-chic look"). 文艺 is short for 文艺青年, a term that was recently much debated on a translator listserv that I hang out on, but basically means "artsy," with a generous dose of "fartsy" on the side most of the time.. All in all, I'd probably translate 文艺装逼范儿 as something along the lines of "artsy-fartsy jackoff types."

无处宣泄青春少男 - "Young men with nowhere else to let go / release / vent."

弄潮儿 - Not so much "cultural pioneer" as "fashionista," I think.

黑木耳 - There is no nice way to put this. It refers to the presumed state of the nether regions of women who enjoy frequent and vigorous intercourse. "Worn-out skank" is probably too nice; the term is pretty unpleasantly visual.

海龟 - Yup, as Baidu says, it's a homophone for 海归 -- returnees, and thus presumably yuppies.