Revealing mistake: When the ship is upside-down and they're trying to get Susan down from the table, you can see that the table really isn't attached to the ceiling. You can see the center pool split into legs that are supposed to be connected to the floor, but when Susan moves around and shakes the table, the legs shake and you can see space between them and the floor. Even if the other legs outside of the shot were connected, the table would be leaning under Susan's weight.
Revealing mistake: When Manny gets to the engine room and spots Belle lying dead on the floor, you can see her breathing as her chest slightly moves. (01:33:35)
Revealing mistake: When the cast is assembled before jumping into the water, the scenery appears to be the same as in the scene where they leave the water, with just a few things moved about.
Answer: He's the representative of the owner of the ship.