If I remember correctly, Gen IV events all use the normal "Mystery Gift" algorithm, where the IVs can be anything and the PID must be non-shiny (if it's dynamic).
But I think Gen III events have different PID-IV correlations, most of which I don't know about.
So:
- What is the PID-IV correlation for event Pokemon from Gen III? I'm mostly asking about Pokemon Box - is it possible to just take a hatched, migrated Pokemon from Gen III and hack the special move onto it? (With the exception of Pichu, since it knows the HM move Surf).
- Are there any exceptions to the "Mystery Gift" algorithm for Gen IV events?