Jungle river trip can be done as part of your visit to a Mayan Ruin (clearly not a kayak though) - the guides will show you animals and explain the plants and things - you will see several kinds of jungle - all beautiful, and will learn a lot!
You can kayak around the mangroves on AC - it's impressive.
The butterfly farms are on the mainland. Lovely as they are, I don't think looking at a butterfly cocoon rates a major detour.