Though there are many people of Sicilian origin in the USA I doubt many of them care about Calcio and or have become assimilated into american culture to the point of not caring much for Italian football. That being said they have a decent sized fanbase and would boost numbesr for Serie A.
All the Sicilians I know living in the San Francisco Bay Area are either fans of Juve, Milan or Inter. This is pretty much true of most fair weather Italian soccer fans though.
You would have to research where Palermitani have immigrated to in the past 30 years. Even then, they may just be Juventini which isn't a surprise even in Palermo. Their best bet for marketing is their hot pink shirt which is unlike any other
the Palermo shirts actually are very famous around the world... everybody knows the Pink lol, even people who've never watched a minute of Serie A will say "Doesn't Italy have a team with pink shirts?" This was before they got relegated though. with that being said, I'm fairly certain if Palermo became a team threatening for CL/EL year in and year out you'd get a lot of fairweather fans of the "big 3" from Sicily cheering on Palermo.
Juventus wore the same colors a few years ago celebrating their 100 year anniversary. You can't beat pretty and pink though!