I'm pretty sure Brock is Asian since he only appears to be dark in the anime and the first manga (Pokemon Adventures).
Some more evolution theories!
-Metapod was intended to evolve into Venomoth and Venonat was intended to evolve into Butterfree. Why? Look at the body structure of Venonat and Buttrfree. The eyes are identical, they both have the same hands and feet and the same mouth. Caterpiw and Venomoth's body structure is the same. Small limbs with a larger body.
-Tangela was originally intended to evolve into Jynx. Tangela had tangled hair that resembled dreads. Upon evolving it gains luscious, maintained hair so that you can actually see its body.
-Team Rocket is the incarnation of Nazis