^^THIS^^
But it's more of a necessity for me then a "want".

The style of the art means nothing if the apperiance of the character(s) resembles that of the subject too much. I'm already straddling the line as it is with his look. For example, if I were to draw a smile on the mask, then Frankie could claim I'm using his Mister Chief parody character. With this particular character (in this design), the suit and body are easy to parody. But the helemt is not. Master Chief's helmet is very iconic. I have no choice but to change or remove details. And including eyes (only) is one such needed change.

Likewise, it's the same reason I can't add "code" details to the girl.
Creating parodies are not easy to design. There are fine lines one must be mindful of.
I'm in the process of creating two-three batman parodies with the same stlye (not same scene). I'm going through the same issues with them. Simply adding a simplified (but original) bat logo to his costume would be crossing that line.
:(