The insurance thing was what made me so convinced early on that he was guilty. BUT.
Did you listen to his explanation? I thought it was really interesting, and certainly verifiable by LE if they want to check it.
Basically, what he said was he took out "trip insurance" for both of them, meaning, as you say, he could get his money back if they cancelled the trip. Then, he went on to add additional insurance for himself in case something happened to him, his boys would be taken care of. Makes sense so far.
He went on to say that you can't "uncheck" the box for both of them. Whatever insurance one has, the other has also. So while it wasn't his intent to insure her, he says, he had to in order to insure himself. Both or nothing.
If that's truly the case, it makes absolute sense to me, and thoroughly explains why he had insurance on her.
And that was my biggest sticking point. He was drinking enough to maybe perceive approaching dark clouds were a storm, whatever, and she could have drowned without any kind of water turbulence. The way people drown in a swimming pool. It seems very clear she wasn't an experienced swimmer because her friends all say she would never have put her head in the water, so it appears she never swam. But I believe someone who "never swims" might be so moved by the beauty of that place, and the thrill of a vacation, to do something they didn't usually do.
I do wish the reporter had asked the question of where did her snorkeling gear come from. That's the final question I have.