Don't know about trading yet, but I heard there was a way to migrate them onto your ds then switch games and load them on xy. Also once u get internet I know you can sign up for the pokemon cloud storage trial, and switch between games. So far I have been making random friends to get lots of pokes in my safari friend park where I just caught a feraligator, and some other older goodies I haven't seen elsewhere. Going to see If i can complete the pokedex without trading, but depends on whether legendaries will appear in the friend park.(i doubt it but well see)