One of the members of cruise-chat is a resident of Cozumel and is documenting the recovery efforts. His website gives you details and updated reports (with pictures) about the conditions on the island, what activities are up and running and in what capacity, etc. Here is a link to Ian's site: http://www.wilmacozumel.com
Since they are limiting the number of ships in port (4 max at this time) the tendering process has been running fairly smoothly. As for booking excursions, if you book your tours independently, many of the tour operators on the island refund your money (just like the cruise line does) if your ship is unable to make it to the port.
Progress is being made there on a daily basis, so it is difficult to say what it will be like in April.
Here is another link to a website where you can find out which ships will be in port with you on a given day: http://www.cruisecal.com/dnn/