A minimum of at least 1 year from now. They haven't even finished rolling the first watch to all the countries. I would expect fall 2016 for the earliest, but probably not till spring or fall 2017. And probably will be Apple Watch S and not Apple Watch 2.
I think it may be called Apple Watch. I can't see them keeping the old internals to sell an older version at a cheaper price. It's fashion as much as tech.
Apple has form. iPad 3 and 4 weren't called that when they came out.