you can't.
no
no
EDIT: I'm not sure either. i tried to trade from crystal to leaf green, and it didn't recognize that i was trying to trade. im not completely sure i think you have to have two-hundred Pokemon on fire red then you can trade from Pokemon crystal.im not sure you can do that with crystal
You'll need to trade for it or evolve your traded Vulpix with a Fire Stone. (Vulpix isn't available in Pokemon Crystal, unfortunately.)
Nope. sorry
No.
No, you cannot trade between the two different versions because the Pokemon are different or the Pokemon know different moves that are not in red version. When they re-make gold and silver for DS there may be some way to trade between Pokemon fire red and leafgreen to the new gold and silver but I doubt it.
yes.
Yes after becoming Pokemon champion in both games you can trade but after firered delivers the ruby and sapphire to celio at one island then you can trade.
the only way to get mewtwo is to trade it from Pokemon red,blue,or yellow. in leaf green and fire red he is in cerulean cave cheat codesxD
You cannot "trade" pokemon between Pokemon FireRed and Pokemon Pearl. Instead, pokemon from Pokemon FireRed Version can be transferred to Pokemon Pearl via Pal Park.
no u cannot