Hey Brian,
Are we on the same cruise? (We are on the Breakaway 6/25-7/4) We have the same itinerary, so I'll share with you where I am in my research so far.
For Malta, we are doing the NCL beach transfer. We have a credit, so it's super affordable and I think we will need a break instead of the tours.
For Messina, the kids really want to see Mt Etna, so we are looking at booking a Mt Etna and Taormina tour. I found 4 companies that all have great reviews on TripAdvisor
Sicily Tours di C. Egitto
Sicily with Sebastian
Excursions Sicily
Sicily Private Tours by Luca
For the stop in Naples, we are looking at doing a food tour. Lots of options, just trying to decide. We have been at this port before and did a ship excursion b/c ours had been cancelled. It was Sorrento with pizza making and we didn't really enjoy it.
For Florence, our first choice tour was sold out, so I am going to do research on that today.
Let me what you've decided to do!