You do the special mission when you beat the game and wait a moment until the mailman arrives at any poke-mart.(waiting can take any limit of time.)
using a Pokemon event
Yes, you can trade them from diamond and pearl
You cant
I think you can only pass Pokemon from Emerald to Diamond/Pearl
The Membership Pass can only be obtained using an Action Replay. The event for this item has ended for Pokemon Diamond, Pearl, and Platinum.
Nintendo event
it depends which man
You can get a membership pass by Nintendo event or mystery gift
There is no such thing as a "rainbow pass" or there is some diffrent name for it.
see 450 Pokemon in the pokedex
Pokemon trainers don't know for sure.
100