there are only gen 1 and gen 2 pokemon in the game until to get the national pokedex, generally after beating the elite four. After that you are able to get Gen3 and Gen4 pokemon since it Soul Silver is a Gen4 game.
Pokemon IV EV Natures and Shinys do exist.
Gamefreak stopped supporting online functionality for those games so you are not able to use things like gts or online battles. so just the story line.
Their pokemon are all lvl 100.
Im sure you can play it on an emulator.
GL.