If the idea is to have characters to be used in one game, then idea B is much better as it gives characters which are about same size and can be used in same game. If the contest allows to make any character then separate submissions are surely so different that you cant put 2 of them into same game.

Plus, I think theme as "zelda character" is way too wide and to make 3 different directions is quite a lot of work. I would think the theme needs to be clear and simple, like "side-view hero walking" or "front view monster bursting fireballs".