Lack of absolute certainty is not remotely the same as total ignorance. I've explained to you what the most likely possibilities are, based on general knowledge of the subject matter, observation of the data, and deductive reasoning. Or rather, I've explained what I'm reasonably certain the explanation is, but since I think intellectual honesty demands openness to alternatives, I've offered a second possibility as well, though I don't consider it as probable. I think if the "auras" cel were far enough above the other cels to be out of focus, it would also be far enough away that the difference in image size would be much more pronounced.
One cannot be intellectually responsible -- or honest with oneself or others -- if one does not admit the possibility that one's conclusions could be wrong. But that is not the same thing as knowing nothing. Honest doubt is not ignorance; it is simply willingness to question and learn.
I don't recall accusing you of being totally ignorant or knowing nothing.
I'm just trying to separate speculation and theory--however well informed and otherwise--from actual knowledge. I enjoy trying to figure out how things are done, but no matter what I come up with, I wasn't there looking over the shoulders of the artists watching all their techniques.
Maybe some of the books listed at http://www.danhausertrek.com/AnimatedSeries/Refs.html
have some of the answers we're looking for here, according to people who were actually there and involved. Besides the new book Lou Scheimer: Creating The Filmation Generation,
by Lou Scheimer with Andy Mangels, there's also Animation by Filmation
by Michael Swanigan and Darrell McNeill. But I don't know what's in those two books, because I don't have them.