yes you need to get the 3 legenderies regice regirock and registeel which can be found on Pokemon emerald ruby and Sapphire
No
no nobody in Pokemon platinum have a doexys.
No sadly
I am sorry to say this but, you cant catch any of the Pokemon in platinum in ruby unless it is a hoenn Pokemon.
yes
there arent dark Pokemon in any Pokemon game.
Croconaw evolves at level 38, not by a stone.
yes it works with any diamond pearl or platinum game
You can never trade Pokemon from Black to Platinum, because Generation V Pokemon do not appear in Platinum or any other game before Black and White. However, you an transfer Pokemon from Platinum to Black after you beat the game.
yes
No
No there are not. larson