Well, actually lots of families nowadays are mixed (north+south) because after WW2 ended, Italy was an extremely poor and devastated country. The north has always been more advanced than the south, so usually women from the south would try to marry a man from the north in hopes to lead a better life.
Nowadays in our generation, perhaps a mixed couple wouldnāt be seen as positively as in our grandparentsā generation (the boomers hehe).
Well, if it helps you, Iām pale as a ghost and Iām from Milan (north). However, itās worth noting that Iām 3/4 northerner and 1/4 southerner. My grandma (from the south) isnāt as pale as I am, but she isnāt dark either, sheās quite light in complexion. All this to say, your character can literally be from everywhere you want. You can use my city if you like!