I know they're kinda difficult to find them, and it would take a lot of time and effort to do so, but I'm just thinking of maybe we could implement this on the wiki, for wiki purposes. As I've looked through various LEGO wikis like the Ninjago Wiki and Brickipedia, they already have their own share of various set prototypes and concept arts.

I too also wonder, how the 5 main characters actually look like and what their names are in concept form, before their current designs were finalized...