You cannot catch it in Pokémon Plantinum, you can only trade it.
There is no Pokemon called "styravia".. What do you mean? Staravia is evolving in lvl 34. Check an online-Pokedex, if you want to know something about evolving...
There is a comic strip cartoon character named Cathy. It's also the name of the strip. Also there's Charlie Brown. There is also Casper The Friendly Ghost. While also there is Charlie Bucket from Willy Wonka/Charlie and the Chocolate Factory! Chip from Chip and Dale - Disney!
Use items or go to a Pokemon Center to heal your Pokemon.
Pokemon 222 on Pokemon diamond is (CORSOLA) there is Pokemon 222 and you have to gts trade or link trade it to get
By Pokemon rangers or cheating
none
yanma
It's already out !
Marry a rich wife
You have to buy Pokemon Platinum. (Its a separate game!)
yes there is some new Pokemon on plantinum. like girantina
turn back cave.
in the snowy mountains but you have to eveolve it
You can only get one
The 4 powerful guys that you battle at the Pokemon league.
pokemon wi-fi events. but you are too late for that.