Fangio strikes me as a very credible candidate for Head Coach based on his vast experience on Defense. However, I struggle to understand why the OP felt the need to bring his Italian heritage into the discussion. Does it matter if Fangio has Calabrese or Sicilian or Napolitano or Tuscan or Bolognese - Italian heritage? For that matter, does who cares if he's of Irish, Dutch, Lithuanian Jew, Chinese or Transylvanian transexual vampire heritage - we need someone who understands football and inspires leadership and also has the ability to develop talent. It doesn't matter to me if he has an Offense/Defense/Special Teams experience.
In a way, Vic Fangio represents a Mike Zimmer type of coaching candidate. Zimmer, as you are probably aware had enjoyed a vast proven defensive philosophy with a tough, strict no nonsense approach to discipline on Defense. There had been a reticence to appoint him as a Head Coach, because it was not perceived as a sexy pick like the latest hot Offensive Coordinator. However, Minnesota Vikings gave him a go and they progressively improved under him until this season.
Hey, I hoped Adam Gase would succeed but progressively his limitations were exposed. His success in Denver was all about exploiting matchups and in Peyton Manning, he was lucky enough to have an elite QB who knew exactly what he was doing. Make no mistake, Gase can succeed again on Offense when he has a top QB and a lot of talent around him. Tannehill's deficiencies have also been exposed in recent weeks. Yes, he's got a pretty accurate arm. Yes, he's a deceptively tough soldier. Yes, he has decent character and won't get into trouble off the field or say something stupid in front of a camera (cough Jameis). However, what has been exposed over and over again is that he completely lacks instincts when his protection breaks down. In comparison, Russell Wilson, Roethlisberger, Brady and even some of the young emerging athletic QBs all seem to have much better instincts than Tannehill - and if Mr Ross is paying $19M a year for a QB, maybe he can get one not completely devoid of instincts.
If Fangio gets the job in Miami, he's going to need good coaches around him - particularly on Offense, but he's also going to need a good QB (who can remain healthy and hopefully with decent instincts when under pressure).