That would have to be Dialga.
arceus
a lot of legendary Pokemon
there is no best spot
That's a matter of opinion(myne is Giratina)
try serebii.net its got a lotta Pokemon stuff
the legendary Pokemon in diamond and pearl are dialga and palkia.
No, a Bidoof cannot evolve into any Legendary Pokémon in Diamond.
Heatran
Dialga
you cant unfourtanately
you can't catch it because you already beaten the legendary
no