no but if you catch all the hoenn pokemon you can catch jotho and kanto pokemon
No u can't
There isn't an eevee in Pokemon Emerald. If you go to serebii.net you can find lots of other way to get eevee in the other games
No you cannot go to other regions in Pokemon Pearl or Diamond version but in Pokemon Heart Gold and Soul Silver you can go to the Jotoh region.
the Pokemon that can use thief are ralts,lotad,mightyena and other dark and psyic Pokemon i cant think of.
The way you get waterfall is by trading the waterfall HM from Fire Red Version or the other Version that have waterfall HM ( you can trade with a link cable or wireless adaptor)
YOU CAN'T
No, Shuckle can't evlove in Emerald or any other version.
I am not certain it is possible to go to other regions in Platinum, but I don't think they are accessible simply because you could do that it in the Emerald version. The only way (in my opinion) to get to the other regions are by using Action Replay cheats.
To find Pokemon from other regions that you couldn't normally get in hoenn.
Yes there are plenty of kanto and mostly johto Pokemon you can find in emerald most of them can be hunted down in the safari zone.
No u can't
There isn't an eevee in Pokemon Emerald. If you go to serebii.net you can find lots of other way to get eevee in the other games
No. If you want to go to other regions you must buy other Pokemon games.
you cant. its just a one region version of pokemon.
you trade with others who has the kanto, johto, or other hoen regions
No you cannot go to other regions in Pokemon Pearl or Diamond version but in Pokemon Heart Gold and Soul Silver you can go to the Jotoh region.
For Emerald Version, you must get a ticket from a Nintendo Event to get Mew. For all other games, you must trade it from Emerald.