withholding skin color, until the end--if that changes your perspective of the whole story, how could that be bad except that it tells you something about yourself that maybe you didn't want to know.I’m not sure I follow... can you expand the concern? Characters probably have a skin color, and it may or may not be relevant. I’m not sure what is going to get ridiculous ...?
The point is that the only problem should arise if one description offered by the author is actually the opposite of another actual description offered by the author.
I don't buy this stuff where some people say they would rather fill in the description themselves, because what it really is is that those people just tend to do that when they are denied a complete description at the beginning and then set themselves up for a disappointment when their preconceived idea is nowhere near what the person looks like.
If the author hasn't given you an eye color or hair color, why would you presume to give the character those? I generally assume that the correct opportunity for description has no yet arrived and could show up any time now.
Without those then the character might show up as flat-2d and if you keep filling them in, then you might fool yourself into believing the author created a well rounded character and the joke is on you because you just did that in your head.