My sympathies Selena, it's frustrating, soul destroying and un-nerving when this sort of thing happens, I read the replies you received on 'another' forum, some of which were not in the slightest way helpful
However, don't be too disheartened. You mentioned that the engine may need to be replaced. Very often, all thats needed with a marine engine is a good clean, maybe a stripdown if its been underwater for any length of time (has it?) and a complete dry out. Is it a diesel or petrol?
Unfortunately the interior will need replacing, but not necessarily the woodwork, unless, again, it was underwater for any length of time.
I know it all seems hopeless, but it may not be as bad as you at first think. I hope it isn't, and I hope the insurance comes across for you.
Had a look at your pics, and I must say from what you've said, it does sound like it was done by someone who knew exactly what to do!!