Who is talking at the Dimensional Scream of the Pokemon and why Wigglytuff appears on it?

Question

For who played PMD Explorers of Darkness/Time/Sky, you know what I am talking about.
It's a vision of the future known as Dimensional Scream.

There is a specifice phrase at the Groudon State, that you have a Dimensional Scream and then it says ''...Good job partner.'' and that makes me suspect that is Grovyle or my team partner.
Sometimes you can see the Wigglytuff in the Dimensional Screams to describe some future acts.

Who really is in the Dimensional Scream and why Wigglytuff sometimes appears on it?

Answer 1

The Dimensional Scream of the Groudon Statue is generally assumed to be Grovyle, the dialogue being a clip of when you were searching for the locations of the Time Gears as a human in the future, with Grovyle congratulating you on the discovery of the Time Gear.

Wigglytuff appears in the Waterfall Cave Scream as he was the one who discovered Waterfall Cave before the player, and so the objects only hold the memory of him being there.

Finally, in the graduation Scream, I think Wigglytuff is only used to show that the box couldn't be a trap, and was placed there for the graduation.