The MAF for a DII is like $200, the DI MAF is $1500.
95% of all O2 codes on a Land Rover Disco are due to the need of a tune up.
Any exhaust part will be to hot to touch after the engine has been running for a while.

And most likely cold water on O2 at the beach would be no more thermal shock than Colorado creek water, or snow pack up to your wheel wells (Eric T on xmas tree expedition). So hopefully some cable clean up, and the standard plugs and wires, but we'll wait on Mr. Terry to fill us in.

And yes, I have brushed against an O2. Just like a soldering iron, they look pretty much the same hot or cold...

Do you think a river that is flooding because of all the spring snow melt and is about 40*F would shock a hot O2 sensor and cause it to fail?

No, I don't, because if it did, you guys would be having that sort of problem quite often. And same for plowing through fresh snow. You're probably right, plugs and wires, reset codes, go play some more.

I hope that is all there is to his codes, and at worst maybe clean out some connectors. I think the first two codes are from the sensors being off line or out of range.

O2's eventually fail, they have an electric heater element inside, if you have older ones, or marginal ones, maybe thermal stress would play a small part. But you are right, if it was widespread we would hear more about it than dead batteries.