EXTREME MAKEOVER: Z-MACHINE POLTERGEIST EDITION
> Nod and turn back to the poltergeist.
> "How about skin tone, then? Perhaps you would like it a little darker, or a little lighter?"
Also it occurs to me that suggesting a slight chest size change (for larger or smaller) might not be a bad idea, due to how personal such a thing can be. (If we do suggest it, we can lead with "smaller" so people can be sure I'm not trying to influence the response. <_<) If Pocky and Brocky reaches the point where she's making that kind of friend, I suspect she's not going to care about keeping the illusion up any more anyway.
Anyway, what other ideas do people have? Hair color and skin tone are now covered. Off the top of my head, there's facial feature rearrangement, eye color and skin marks (such as freckles) all available as possibilities. Height seems to be out, as do all actual body shapes that risk being noticed through casual contact (limb length and width, shoulder width, pudgy vs. thin, wide vs. narrow hips, etc.). Chest size could work here since, again, I don't expect anyone to be touching her there until she reaches a point where she'd drop the illusion in the name of intimacy anyway, but I would fully understand if people want to just let it go and move on to something else.
A potential problem in dropping all body shape adjustment, both ones that would be casually noticed and ones that would need intimate contact, is that I'm honestly not sure what other options we have at our disposal. Palette swaps are cute but they don't do a lot to make one think "that's a different person entirely".