no
You can't.
No you cannot.
In Diamond & Pearl? Impossible without migrating, trading, or Action Replaying.
not without an action replay and a Pokemon modifier code.
you can't
you have to get the arceus event on mystery gift.
you cant
Yes, but you will need the member card.
that's impossible you actually cant
It is imposible without an Action Replay unless you get it in a GBA game and transfer it to Diamond/Pearl throu pal park.
Action Replay. Sorry, but you can't get ho-oh without it.
Catch it in firered or leafgreen, then migrate.