True. Instances of "survival" in my original statement should probably be read as "reproduction". There are, of course, more selection criteria available than just "survival to reproduction age". And selections can work opposing each other.
But, in all, the original statement still stands: Selections only work negatively. That is, a peacock with better plumage might get more chances of reproducing due to sexual selection, but as long as he gets at least one chance of reproduction, he has not been selected against.
Reproduction causes a loss of half of the chromosomes. If he only has one offspring (unless it is a lot more sexually successful than him), his line dies out.
Different organisms have evolved different reproduction strategies through selection:
You're being pretty pedantic at this point. If an individual reproduces, then none of that individual's traits were sufficiently selected against. That's also not a guarantee that all their traits will carry on in new lines. There's also no guarantee that their children will be fit, due to differing traits or changing environment.
But, in all, the original statement still stands: Selections only work negatively. That is, a peacock with better plumage might get more chances of reproducing due to sexual selection, but as long as he gets at least one chance of reproduction, he has not been selected against.