Re (3): there are a lot of accounts online of divers filling their cheap Casios with some oil or paraffin, so it can stand to be submerged. I guess that if it's

Re (3): there are a lot of accounts online of divers filling their cheap Casios with some oil or paraffin, so it can stand to be submerged. I guess that if it's good enough to stand pressure and coating the surfaces of the PCB to avoid short circuits, it's good enough for high humidity places. Maybe not good enough for soap and shampoo, but still a great upgrade.