For Parasailing try Elvis. He will find you. He is usually on the beach close to the swim up bar. He doesn't work for Couples but he will take care of you. He lined it up for us and told us to pay him what we though it was worth. Told us no hurry just pay before we left to go home. Very trusting people and it was a lot of fun.
As for zip lines, I've never gone but there are 2-3 about an hour away from CSA. Search a few other recent threads about them for some details. YS Falls, mayfield falls, and Chukka Canopy.