I'm sure Milan was red and white, with the 'ducal guard' or 'civic guard' in just green (hence the colours of the current Italian Flag)... but memory might be failing me there and it could relate to a later time.
As far as I recall Swiss mercenaries, like the Landsknechts, are supposed to have wore what they pleased, unlike the cantonal troops themselves who were uniformed... the whole slashed fashion beginning with what they liberated on the battlefield and subsequently wore after 'altering' it to fit.