I would recommend getting your passport ASAP just to ensure you receive it in time. Don't wait too long to start to work on that. If you already have a passport, check to make sure it won't be expired. The current processing time for passport is 6-8 weeks.
There are a handful of places around the island that accept USD but most places prefer pesos. There are currency exchange ATM's all around the island for a small fee. However, it is recommended ahead of time to exchange your currency to avoid the fees, however, the fees really aren't that much or something major to worry about if you are unable to exchange your currency in advance.
We do not recommend drinking the local water on the island. All of the water you will drink will be bottled. The ice along the island is all filtered and nothing to worry about, and the locals will provide you with bottles already so you will never have to ask specifically for bottled water. We also advise brushing your teeth with bottled water just to be safe.
We have hired an amazing photographer/ videographer and want you all to be in the moment with us. Therefore we are having an unplugged ceremony, so we ask you to please not record or take pictures during the ceremony. Ex. Cell phone, iPad, camera, camcorder, etc.
If you have a non-emergency, we recommend you call our wedding planners Alex and Tiffany at (+521-998-203-6830). They will translate and make arrangements for a house-call. Dr. Salas (+521-998-845-2370) has a private practice and speaks English. If it's an emergency, you can ask the front desk of your hotel for assistance. There are larger hospitals in Cancun if more attention is needed.