It really depends. While I think that Italian unification in the modern era is likely, I do not think that it is overdetermined, and there's a lot of flukes in the way it actually happened. Sicily and the Northeast, as noted, are the bits more likely to go on different paths, but it really depends on how unification happens and what areas and social groups lead it. If the House of Savoy is involved, Sardinia is going to be part of Italy with a POD after the early 18th century, even if it is culturally and linguistically distinct from continental Italy. Trentino could have easily have stayed Austrian, likewise Trieste and the rest of Venezia Giulia (perhaps for the better, regarding the people involved) could have easily gone on a different path.
Valtellina could have easily remained Swiss with a Napoleonic era POD, Aosta Valley (and maybe also Susa and other Alpine areas of Piedmont) might become French under conceivable circumstances at verious times.
Of course, PODs where the Kingdom of Naples survives are very possible.