Yes, Sicilia and Corsica have a lot in common. It's still Mediterranean Sea, and truly saying Corsica may have more to do with Sicilia than Mainland France.
And second yes, everybody is a "mix" of different nationalities; one can be 'pure' German/French, but only to 4-5 generations back. There is always some "foreign element" in the family tree.
I can say that going 5 generations back, all my ancestors are Poles. So I'm quite pure
