What does Bishoujo mean? I'm sure that is your first question, since it was mine as well when I first heard it. Here's the definition:
Bishoujo - (Japanese) beautiful young girl.
Apparently that is all this word means. It does not refer to a specific genre or set of stories. Instead it simply seems to be a style directly linked to the various beautiful looking young (under college age) girls that have appeared in Manga/Anime (Japanese animation).
Kotobukiya, a Japanese company that has both a Marvel and a DC license, got the clever idea to take the female characters from these companies and turn them into Bishoujos. As of now there is a whole set of these that have been produced (ie Phoenix, Psylocke, Rogue, etc.). I have decided not to collect them though since doing so would take my collecting trajectory in a new direction.
The first statue in the Bishoujo line I thought I would feature is the Jean Grey statue that was released in 2011.