I have to agree, no way did Rocco Sollecito fall out of favor with Vito. It just doesn't make sense plus the fact him and Vito were very close for a very long time. I would definitely agree that if that was true for anyone it would be Arcadi over Sollecito and we still don't really know what side Frank is on.
Same for Stefano becoming a leading figure too, no way would Vito trust the family after his death if Rocco had turned on him.
And Sinatra is right, Vito did have some business dealings in Italy/Sicily so it only makes sense that what seems to be his best friend would have some dealings there too.