Hi, for Naples here is what I recommend. List is grouped by neighborhood so that might help with your overall planning.
LungomareThis is along the bay (Via Partenope) and is pedestrian only. If you are in Naples in the evening, this is a great place to hangout. Mostly tourist spots but if you choose wisely it is great.
Pizza - Sorbillo - Lievito Madre al Mare, they also have excellent Gluten Free pizza if that is required
Dinner - La Casa di Ninetta
Gelato - Desìo Gelato & Pastry
https://www.tripadvisor.com/Attraction_Review-g187785-d8028191-Reviews-Lungomare-Naples_Province_of_Naples_Campania.htmlhttps://www.yelp.com/biz/sorbillo-lievito-madre-al-mare-napolihttp://www.italiandesio.it/La PignaseccaNaples oldest street market. I had a great lunch at Pizzeria Al 22. They also have many non pizza options. This market also has several seafood merchants that sell fried seafood snacks.
https://www.tripadvisor.com/Attraction_Review-g187785-d8041178-Reviews-La_Pignasecca-Naples_Province_of_Naples_Campania.htmlhttp://www.al22pizzeria.it/Centro StoricoThis is the historic center of Naples.
Pizza:
- Gino Sorbillo, be warned the line will be long. I personally liked the pizza but I'd rather not spend my time waiting here.
- DiMateo - pizza and fried foods
While not exactly in the historic center, but a few minutes away is the famous L'Antica Pizzeria Da Michele. Well worth the wait for this one, you will not find another pizza like that in Naples or elsewhere.
If you only have time for one pizza stop, this is the one, even with the crowds. Yes tourists go there, but it is excellent.
https://www.napoliunplugged.com/saturday-stroll-the-classic-tour-of-centro-storico-part-1.htmlhttps://www.yelp.com/biz/sorbillo-napoli-4https://www.yelp.com/biz/di-matteo-napolihttps://www.yelp.com/biz/l-antica-pizzeria-da-michele-napoli-2The food in Naples will be very familiar to America tourists, since it is mostly the basis of Italian-American cuisine. Since you love seafood, Naples is perfect. Any pasta with seafood is a great option, especially vongole (clams). Don't fret about finding a place that only uses San Marzano tomatoes; however if you see Piennolo tomatoes, well worth the try. These are exclusive to Mt. Vesuvius and rare to find outside of Naples.
Since you like hearty red wine, you will love Aglianico. That variety is the king of Southern Italian wine and you will find it everywhere. I'd also recommend spending few extra bucks and get Taurasi wine if you see it on a menu.
Don't forget to try both mozzarella di bufala and ricotta di bufala.
Let me know if you find any bad espresso in Naples, you won't

Your teenage family members may enjoy
https://www.napolisotterranea.org/en/naples-underground/Enjoy your trip.