We loved Dolphinaris in Cozumel! I would definitely recommend them if you’re wanting to do dolphins. We did do the Dolphin Exclusive VIP excursion which is outside of age ranges for you but the Dolphin Swim looks pretty much the same. I will say that we saw a family which at younger child (probably around 2-3) who was freaking out. They were absolutely terrified of the dolphin, so you may want to consider that if your kiddo hasn’t ever seen a real dolphin. They’re much bigger than you might expect. If you read trip reports Timon did a really great one about this. A family member of ours was also recently there with a different cruise line and loved it too.
We did the exclusive and fun beach break in Falmouth and I wouldn’t recommend it. We had intended a calm day but had someone stop by every few minutes to try and sell us things, they also had a dolphin area here but it was sad. The guy trying to sell it to us stopped by at least every 15 minutes with the same pitch. They then set up a cooking demo directly behind where we were sitting with a mic that kept having feedback issues and was turned up really loud. We wanted to leave so badly. It was comical how bad this excursion was
These things could have changed since it’s been a few years but I would still never go back.