Here is a link that will help you. http://www.serebii.net/pokedex-dp/
no
All, provided you have seen them.
You can't, you'll have to trade.
you can start over
The Legendary Pokemon in Diamond are Dialga, Azelf, Mesprit, and Uxie. That's all I know of.
yes you can but it is dialga not palkia
The legendary Pokemon are: Palkia,Dialga,Uxie,Mesprite,Azelf,Heatran,Regigigis,Shaymin,Darkrai,Arceus.
yes....all but the legendary's
You can get Dialga Mesprit Uxie Azelf Giratina and if you somehow get regirock, regiice, and registeel on to diamond you can also get regigigas
You have to beat the elite four again it works in all games
No. You need codes and a friend who has pearl. (and Pokemon ranger) or YOU could have Pokemon pearl and Pokemon ranger not just your friends.
The names of the Legendaries in Pokemon Diamond are Uxie, Mesprit, Azelf, Dialga, Palkia, Heatran, Regigigas, Giratina, Cresselia, Phione, Manaphy, Darkrai, Shaymin and the rarest of all Legends in Diamond; Arceus.