regarding the taxi, there is a fixed rate from the airport to any hotel in Naples but you have to ask for it before boarding the taxi, so please ask for "Tariffa Predeterminata" it should cost no more than 26 euros.

I attach a table here, look at the AEREOPORT (airport) column, and if you are going to Hotel Majestic the city area is called Chaia so you have to pay 23 euros. They always try to cheat so do not give them any extra money and if they insist call the porter at the hotel ;)