Be weird that's what quirky means and if you can't look it up on Google or check searbii
If you're a female, get a calm nature, if you're a male, get a quirky timid.
Yes, just like darkness and time, you can be Piplup. You have to be a Impish Male or Quirky Female to be one though.
in mystery jungle after you get secret rank
Yes, but only in Pokemon Mystery Dungeon: Explorers of Sky.
no
You Can't
You have him/her as a stater pokemon.
No.
You can't breed Pokemon in the mystery dungeon games.
Unfortunately you can get Arceus in Explorers of sky :/ The closest you get to seeing it is a statue...
It's the Darkrai battle, as also seen in Pokemon Mystery Dungeon Explorers of Time/Darkness.
female relaxed