Hi Paul,
On the footstrap question, I`d replace that one with windsurfer style footstraps, they are adjustable. Adjust so that your toes only just stick out past the strap, no way your whole foot can go through it & get your ankle trapped. I`ve had some exciting wipeouts on short-boards and never got a foot stuck.
The other 2 questions I`ll leave to others. If your trailer has good cradles & well-padded, the boat should be fine. (F16 are not built as light as A-class). The cell-phone issue is contentious, if you`re bobbing in the water you might be out of range, but rather have one than not.
I`d add flares, and a beach-buddy (someone who knows you`re out, and will hit the panic-button if you`re not back by Thursday !)

Cheers
Steve