serebii.net has a lot of useful hints that can help you out if you need info on where to find Pokemon :)
diaga will run away but he will leave the andement orb
(and who cares anyway???)
i think you have to have Pokemon diamond to get him or her whatever.
At the spear pillar.
u can't
you dont
i don't know but diaga evolves into arcues
Yes. Just trade it from a diamond game.
spear pillar at lv.47
You disappear and you reappear at the beach
Go to all the lakes after capturing diaga
stone pillar after beating Cyrus