Looks good and good on them being able to share the feeling of kiting. I am not sure if you were joking but don't use one harness around 2 people. With a little force, one person will squash the other, and potentially very bad.
nah i agree
i reckon you're gonna need a release system between the two harnesses . if you go down in the surf and get tumbled you're gonna be in a world of trouble trying to sort yourself out
Flat water though, not really any issue. way safer!
Maybe you just Cara INA from your front to their handle at the back? If you have two harnesses this might work. They should have also showed a video of the bloopers!