I don't think that this had been brought up, but something which I've noticed is that the edited melon lips seem to use colors outside of the original 16-colors palette for the CGA/EGA/VGA (as used in EGA/VGA mode 0Dh for Keen Dreams).
Reposting here so people can see what you're talking about:
Looks like they turned the "racist" original sprites into a slightly squished version of Mrs. Pac-Man wearing lipstick. Or of regular Pac-Man wearing lipstick, whatever.