If no one said it yet, for your hubs.
Just pop off the cover and drain. It is pretty easy actually. Then you clean up the gasket/sealant already on there, get it down to the metal.
Apply some
Permatex and follow the dirrections. Typically you want to apply it and let it sit for five or ten minutes, then just screw it back on. Let is dry for an hour or two before you refill, and then it will not fully cure until 24hrs (so no water crossings).
The stuff is far and away the best brand for that sort of thing. ANY auto parts store in the USA will have it.
By the way, how fast were you going through that water? With the depth that it is in I should think that employing standard water crossing technique should have gotten you right through. Nice photos at least, and VERY glad to hear it was easy to get running again!
Brian