(1) AFAIK there isn't. Look carefully at all the buttons and read the help file thoroughly, maybe one has been implmented since the latest DOS version.
(2) In the same way, I recall that any IA will require a specifically designed map to switch over to 'landing' mode; that is, the beach generator doesn't only edit the map outlook but also the way the IA handle it.
Now if you plan the human player to do the landing, that is no problem. But anyhow it is safer to split out a beach map and then fill in the superfluous water hexes.
(3) 150m vis at sea? I gather the visibility rating will mostly drop out due to dust, rain, fog, etc. So 3 hexes will be monsoon or thick smog.
On a clear but cloudy night, your NV devices will work just as well. So maybe something in excess of 10, and turn your screen's brightness way down!
Regards