1. I'm pretty sure the Japanese V3 only has Japanese characters but I could be wrong.
2. You should be able to tell if you have played a Connection Tamagotchi before, if not, there's many guides floating around here.
3. I really enjoy the V3, so I would say it is
They shouldn't corrode, but stuff happens.
To get the corrosion away, I'd recommend mixing baking soda with water, and gently dabbing the battery compartment, with the mixture on a q-tip.