Found this on German site, looks legit.
Here is the list of required VS matches
Ness 5
Marth 10
Luigi 22
Falco 50
C.Falcon 70
Lucario 100
Snake 130
R.O.B 160
Ganondorf 200
Mr.Game and Watch 250
Sonic 300
Pummeluff 350
Toon Link 400
Wolf 450
Can anyone else confirm?