Well, that's an impressive list indeed. Here are my comments, FWIW.
1) There are at least two completely different Veggie Man concepts. They should count as two.
2) I would not say that there are two April/December's. The two-panel version is only an abbreviated presentation of the four-paneled one.
3) Same thing with the Flying Dutchman. I'd say two, not three. The two-paneled one (the one actually used) is only an abbreviated presentation of the 6 paneled one, even though the ghosts are all gone by doing that. The original ship-approaching version, though, is very distinct.
3) Two Black Knights? If you mean the original and the 2005 version, I don't see enough change to justify calling those two different portraits either.
4) Ken Anderson described some portraits for his proposed Haunted House. "A maiden aunt with a austere face will coyly wink" can be recognized in the four-panel Apr/Dec, and "a gay blade will disintegrate a la Dorian Gray" is obviously Master Gracey, but there is a third one with no counterpart. I would count it, since it got to a concept stage at least in words. I've tossed together something to remember it by, using an Anderson frame:
5) I've never seen it, but it's been reported that the Sinister 11 "Ogre" was originally supposed to turn into a Cyclops.
6) GRD, I believe, reported that there was a portrait based on the Daphne myth (she turns into a tree as her lover chases her).
7) The wilting flower and the farmhouse certainly do not belong with the souvenirs, just because they made lenticulars out of them. They made lenticulars out of a lot of them. Flowers and Farm were real proposals for real changing portraits.
8) Speaking of, I think it's a real stretch to include the glow-in-the-dark souvenirs on a list like this, but that's just me.