I like the idea of using the wall jump to your advantage during the boss. It's certainly a clever idea and puts the move to good use, so nice work. I'm a bit skeptical about though the use of the GHZ wall object (44) here as it doesn't seem to make much sense from a perspective point of view, with the lighting the opposite way round to the other walls. Of course, if this is from a personal decision, then disregard what I said.
I'd say full shadow; the only reason for this though is because, ironically enough, the original GHZ used the full shadow on right-side walls and lighting walls on the left-side walls. All of the other art (I.e. Moving platforms, rocks etc) also have the lighting this way.
I'm partial to A myself, but I understand some may want the indigo. The difference palette wise is that A has no indigo and two shades of fuchsia while the other two have one shade of indigo and one shade of fuchsia. + - If you can figure out what this is for, you win a cookie
Personally I like the Head from a) and the Body from c)... But due to pallete trickery, I'm sure you can't mix and match like that so I'll go with c so she doesn't look like a Robotnik Minion in all that grey!
I have no huge preference between A and C (if I say C, it'll look like I've succumbed to peer pressure :P), but I'm not a fan of the blue pixel dithering on B.
