One month out.
The AI on Costa Maya didn't pan out, it was fully booked and even the the wait list was closed.
I found another "beach club" Tropicante, while not an AI, has good recommendations in regards to food and drinks. The prices seem reasonable. I have reached out to them and have two loungers reserved at no cost with the understanding you buy some food and drink while there. They have been very responsive and no out of pocket expense, so if seaweed is still an issue, we may just show up by taxi, have a drink or two, and be on our way.
For Cozumel, we will just do some shopping at Los Cinco Soles, and I will imbibe on some local beverages