Xero looks very much like Neku Sakuraba. :| Just saying.
For the female character considering that you used so little back for the outlines I'm quite confused with the solid black outline for the yellow backpack and headphones.
Same goes for Tropic Scythe's black outlined white pants.
Lapras girl has 90% solid black outline, except one wonky hand which has no outline and a little of her chest.
Dusk's white bands too.
Basically you've got an over abuse of black, even though some sprites don't show this problem. It's only the ones that have heavy editing, and for me I know I'd rather not have my trainers have a large sign they are edited.
Your last set of trainers shows a somewhat overuse of black, mostly the second one, but it looks a bit better. That girl is going to fall over if she's by herself by the way. You don't separate couples, they lean on each other too much. :3
I was trying to look at all the others you put in that post but I think photobucket ate it. There is no clarity. D: