There is no problem if you are careful.
(1) Minimise the time in the hover and very little or none will be blown into the intakes. Ponce about for a couple of minutes looking for a pretty spot to land will instigate recirculation through the rotor. You don't have to rush it, just be sure of where you are going to land before you get there.
(2) No.
(3) See (1).
(4) Avoid landing on wet sand. The residual salt will corrode the bottom of the skids over time. More importantly, if the engine fails to start the tide will come in and drown it.
Enjoy the beach.