Yes! All guests will need a passport. Please check to make sure yours is current. Airlines can refuse to let you board if your passport expires within six months. So the ticket here... apply early! :)
Yes! Isla Mujeres is s small island that is for the most part, free of crime. There is a reasonably large Navy Base on that island, which is a great presence when it comes to keeping things very tranquil locally in Isla.
CARM tours & transfers service is available to bring you from the airport to the Ferry Port where you will take a 15 minute ride to paradise! Please see the "Things to do" section for the link to sign up for the round trip Shuttle and Ferry transfer.
The Mexican Peso is standard currency used in Mexico. Everyone in Cancun and Isla will take US Dollars or Mexican Pesos. However, locals do recommend always paying in pesos. To get the BEST exchange rate, they recommend getting pesos from a bank in the states. You can also exchange money at the bank in Isla Mujeres as long as you have your passport with you. They do NOT recommend travelers checks. Pesos are KING!