You can get a shiny Palkia in Pokémon Pearl by doing a soft reset in front of Palkia before fighting it. Do a soft reset by holding L+R+Start+Select.
To soft reset hold down L+R+START+SELECt to return to the title menu.
UP+SELECT+B at the title screen
Hold A, B, Start and Select.
yes it will change the time in Pokemon in either Pokemon diamond and pearl.
r+l+start+select
Soft reset for Pokemon Diamond is R+L+Start+Select.
black berry 8120
You can get a shiny Palkia in Pokémon Pearl by doing a soft reset in front of Palkia before fighting it. Do a soft reset by holding L+R+Start+Select.
Soft reset
Yes.
To soft reset hold down L+R+START+SELECt to return to the title menu.
L+R+Select+Start
UP+SELECT+B at the title screen
To catch Mewtwo in LeafGreen or FireRed no. To migrate Mewtwo from LeafGreen or FireRed to Diamond/Pearl/Platinum yes you have to have it in Diamond/Pearl/Platinum.
You could cheat or soft reset.
No you don't, you will rarely encounter them in the wild.