you can cheat or trade with friends and if you do so you could breed with a Ditto(you can do this after the Pokemon league)
no
No.
Piplup is a starter Pokemon in Pokemon Pearl. you can get him early in the game as your starter Pokemon.
Trade them from other versions
The starter pokemon for Diamond and Pearl are Turtwig, Piplup, and Chimchar.
No, you need to trade or transfer them from Emerald.
No. But you can trade and get all three starters. N&L
No.
trade or use action replay or a RSPG card
you can't
no only 1 starter
your starter Pokemon if you can