All that Griffo said plus..
Forget the cumbersome lifejackets of years ago. These days, they are known as 'Personal Floatation Devices' and are very comfortable to wear whilst flying. Perhaps go to BCF and buy one for each pax? I went for a "PFD Manual Level 150/150N." These importantly keep ones head out of the water.
Cost? Less than $100 each so a no brainer.
(UTR, The lilos have only been "tested" heading north. Not south..
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