They could, as we know that Black Hand did work with Panau (from JC4 intro). And do you remember that "foreign mercenary" that we needed to eliminate? I have a theory that this man was actually from the Black Hand.

He could simply be a normal mercenarie but at the same time could be a black hand mercenarie

I think it was showing all the states rico has invaded

It only showed mendoza and di ravello not panay