Hi Anthony! I'm from Sardinia so I can help you with that. The Sardinian situation is very similar to Hawaii, we have our own language but it's slowly dying so most people speak Italian. My advice is to talk to anyone under 70 and you will be alright.

Don't worry, they speak Italian. My mother is from there. They also use dialect a lot but not when they talk to tourists of course. You'll have a great time, people from Sardegna are famous for being very friendly and warm and I can assure that it's absolutely true

Sure! Every region of Italy has its own dialect: Sicilian is different from Romanesco, for example, and so on. Look at here: https://en.wikipedia.org/wiki/Languages_of_Italy . And Sardinian is a language because, paraphrasing a popular citation, it is a dialect with an army and a navy :-)

Sure you can find many person who can speak italian well