You can.
you cant. You can only catch it in Pokemon emerald, but, you cant catch latias in emerald.
you cant
you cant catch them you have to evovle trapinch
you cant
u cant
you cant you have to migrate it from Pokemon emerald
you cant get regigigas on Pokemon emerald its to ew of a Pokemon
You cant on Emerald, but i believe you can catch and transfer them from FireRed and LeafGreen.
you cant unless you use action reply
you cant you have to migrate it from emerald
you cant catch rayquaza you must trade it from emerald
You cant catch a wild ludicolo. You have to evolve it from a Lombre