For the ocean issue, the problem is that the ocean mesh has holes in it for islands. What I do is just fill them with either terrain if you can, or build a small island from rocks.
As for the lighting and weather, it’s kind of complicated. Unless you either provide the map for someone to look at or start explaining in more detail I can’t really help you beyond basics.
One thing to check though is make sure all your lighting stuff is is in the same level (I actually have it all in a lighting level, but I’ve seen it recommended to have it all in your persistant level.
Also you may need to open each matinee and make sure each track has the correct actor assigned to it. The easiest way to do this is to go into the island map and open each matinee, then write down or screenshot all the settings as well as reverse engineer what actor is assigned to what track.