Leafgreen and Firered, Pearl and Diamond
no but you can get from the other versions
you can get Pokemon that are not in the other version
I think you can only import them from other versions.
Trade them from other versions
Yes, but not all.
yes, in other versions of Pokemon
nothing
Celebii is not catchable in Pokemon diamond. You have to transfer it in to Diamond from other versions that have Celebii in it.
your game boy versions shouldn't real.
yes, but not to any of the old games, only between other silver versions, gold versions, or crystal versions.
there isn't a cheat but you can trade them over from other Pokemon crystal versions.
Staravia will evolve into Staraptor at level 34. This is for Pokemon Diamond, Pearl , or Platinum Versions. The level may be different in other Pokemon versions.