2) Looks very cheap, but it might still be decent. There is no listing of what components it has, which is generally a bad sign. Do you have the ability to check one out in person? If so, take a look at the components and lift it up, if its very heavy, it's probably Hi-Ten and in that case, I'd pass on it.
3) Never head of the stuff. Common steel brands that most have heard of are Tange, Ishiwata, and Reynolds. But even a name doesn't guarantee quality so can't really just go by that.

There are some members here from japan here, and I can't remember what they all ride, but they should be of some help.

Just wondering, wouldn't some of the large companies (Fuji etc.) have bikes for the domestic Japan market?