There are wedding planners at (most) all resorts. While I have no specific info on Mexican laws and resorts, we did research on international weddings before we got hitched some 18 years ago. Here are a couple of takeaways.
In predominantly Catholic countries, subsequent marriages of divorced people is forbidden. Mexican marriages should be considered 'renewal of vows' where the actual marriage should be performed in the USA in order to be fully legal. Same with marriages aboard cruise ships. Foreigners can be married in Greece, but all former marriage and divorce paperwork MUST be translated into Greek and approved before it can take place.
Because of these (and other) limitations, we brought DW's dad and grown kids and had our particulars posted on the registrar's office and our wedding performed in Scotland by a retired Church of Scotland minister at a historic palace. We had a piper, I wore a kilt, and 'claimed' my DW for my clan. It was lovely. 3rd time's the charm!
Jim