Life jackets a must, especially need proper fitting and comfortable.
I am not sure I would clip into jack lines as going overboard, being dragged has risk of drowning and crew with tether needs to be able to detach, depending on situation.
Definitely teach "1 hand for boat and 1 for you".
Also, No leaving cockpit without specific adult (Mom? Captain?, Dad?) being informed and aware.
Monohulls vs catamarans has different issues. Yes, monohulls more contained (for better or for worse) but heeling results in maneuvering on deck issues.
AND SUNSCREEN!
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