I'm not sure if I understood correctly Your questions, but I'll try answer them to my best.
1) Review of works relates only to works in the mainsite archive, and so does adding "corrupted image" or "non-standard style" marks. I have no means to add these marks to drawings on this forum, and especially to those already saved to your computer.
Review is an ongoing project that started about a year ago and will take around 2 more months to complete. I'm afraid that until it will be declared complete, You'll have to consider anything you have downloaded and used as "suspect".
2) I would never encourage anyone to clean-up someone elses works from the archive. If they are messed-up, then they are messed-up. End of the story (I'm doing some cleaning-up as part of the review, but it's only about fixing some stray pixels here and there, making some line that ought to be black but isn't genuinely black etc. - those marked as "corrupted" have HUGE amounts of such issues, fixing of which would take disproportionate amount of time). Original authors - if they are still around - may fix them if they want to.
And if you want to draw a ship that someone else has already drawn, you're free to do it and there is no need to have that fact marked on the "old (already made") drawing. It's kind to ask the author of such old work, but hardly a requirement, considering that lots of once-productive artists are no longer active and there is simply no way to ask them at all.
(another thing is that if you want to draw such "already present" ship, then it never hurts to ask yourself "can I really do it any better than it already is?" - but that's a completely different thing)
EDIT: And obviously, if You were to use any parts of the "old drawing" in Yours, then all previously existing conditions apply (including the CC license provisions) - but You can't "adopt" someone's old work.