Fair warning: This storyline is somewhat improvisational fun (again). I have ideas for it, but this is one of those "as we go dealies", meaning it could be anywhere between 6 and 600 comics long with varying degree of canon-ness. We shall find out together.
As previously commented, change blindness is not an invention of the comic. It is totally a real thing, and refers to something specific. I would argue that transforming one's self without noticing it is a separate thing, though I suppose if one would've noticed if they'd been looking in a mirror, it's nonetheless applicable... Hm...
In any case, this is pretty much an excuse for Grace to try and transform a lot in various ways without people noticing (with varying degrees of success), and for me to have her marks be whomever I feel like. LET'S GO!
Actually, wait. Before we go, I orignally had the second panel shaded as though there were proper room lighting, but the whole point was that there was a lamp missing, so... yeah. Since I made it anyway, here's more properly lit Ellen: