@Robert Columbia,
Our Mexican member seems to know a lot about Balkan and Italian history and population genetics. There are not the kind of intense ethnic divisions and animosities in southern Italy that there are in the Balkans. In my experience, most Arbereshe, and Griko speakers, for that matter, consider themselves "Italian" in the broader sense, especially if they are identifying themselves to people from outside Italy. I've met people here in the states who identify as "southern Italian", and only after years did I discover through a chance conversation that they were half, or even, in one case, 100% Arbereshe. This is even more true for Griko speakers. Three out of four of my husband's grandparents come from a community that spoke Greek until the early 1700's, yet they wouldn't dream of identifying themselves as anything other than southern Italian, and proud ones, at that. In the case of the Griko speaking people, I think we have to remember that until the 1200s the vast majority of southern Italians spoke a form of Greek. It's just been a gradual whittling away of the language. I don't think there's much more than 60,000 Griko speakers left.
In terms of the religions, the Arbereshe of southern Italy who still practice a separate "rite", are part of a group that could be called "Eastern Catholics". There are somewhere close to 22 of these groups. They are in total communion with the "Roman Catholic" Church (acknowledge the supremacy of the Pope, believe in all the same formulations of dogma), but follow the rite (Byzantine) of the Eastern Orthodox Church (the form of the Mass, the use of Greek as the sacred language) and some spiritual traditions of those churches. (Their liturgy is very beautiful, in my opinion, as is the Orthodox rite upon which it is based.)
In Albania, it's my understanding that the majority of the population descends from people who converted to Islam (somewhere around 60-66% ?) The remainder are Christians. It's also my understanding that originally all the Christians in the area now defined as Albania were Orthodox Christians, but in the north (among the Ghegs) there was a conversion to Roman Catholicism. Today there are both "Roman" Christians and "Orthodox" Christians.
Strangely enough, through my Venetian cousin in law I knew an Italian priest who was sent to a Gheg parish.
Anyway, I think it's true that within the next 100 years there won't be any Griko speakers or Arbereshe left in the sense of really distinct groups. This is despite the fact that the Italian government protects minority rights through its constitution, going so far as to provide for nursery school education in Arbereshe and Griko if parents request it, three hours a week instruction in these languages at higher school levels (again, if parents request it) and all sorts of programs supporting their unique cultural events. The Greek government even sponsors classes in Greek for adults, and at one time even paid for the children of Griko speakers to go to summer camps in Greece. It doesn't seem to be working.
I sometimes think that, paradoxically, the more tolerance you show for minorities, the less threatened they feel, and the more they are included in the wider culture, the more quickly they assimilate.
Anyway, there are some pretty famous people who are of "Italian" descent, who actually have Arbereshe descent.
If you're American, you may be familiar with Regis Philbin. He always said he was half Italian, but that Italian is actually Arbereshe.
https://en.wikipedia.org/wiki/Regis_Philbin
A famous half Arbereshe Italian is Antonio Gramsci, the leader of the Italian Communist Party. Francesco Crispi, one of the leaders in the movement for Italian unification (associate and friend of Mazzini and Garibaldi) was born into an Arbereshe family, as was Tito Schipa, the great tenor. There are others, of course.