Is it possible to catch all the Pokemon in cystal?
No unfortunately you have to trade some Pokemon for them to evolve so you need some one with pokemon crystal, sliver, or gold to trade with.
It is a long and hard proccess, but if you are a PokeGeek and you put your heart to it (like me) it is very possible. You have to catch all of the wild Pokemon, legendaries too, trade from other games, restart games, etc. But with about 3 Pokemon you HAVE to cheat. Otherwise it is very possible if you take them one at a time.