1. Do you represent as a race you're not in RL? (And does it matter?)
No, and no, it doesn't really matter. For me, I feel most comfortable being what I am in RL and taking it to SL. I'm Black in RL so I always want to take that to where I go, to the best I can.
2. Can you find good skins, shapes, etc, in SL to achieve this.
Honestly, I haven't had luck with any shapes. Most shapes, as I think one said, have more narrow noses (which is fine) but I know for myself that I don't have a narrow nose and I am fine with that. In the end, I had to make my own shape, based on a picture of me. For skins, it is good now. There's a decent selection of dark skins from The Body Co, Adam and Eve, Dutch Touch, Uzuri (they are nice, but hate them on me) , and MOJO. Also Chain and Vine, L.Fauna, Tuli, and Fresh Fx have nice tones too. However, marketplace has some gems as well.