I think I can answer part of this, at least.
Besides a drawing meeting site standards, what are other criteria used to determine which drawings get uploaded and which do not?
none. being a real/never build design, being somewhat accurate (but this is only really checked on 'popular' ships, and mostly before uploading, or far after
) are the only real criteria apart from meeting the standards. other then that, the only real reason to reject an drawing for upload would be an superior duplicate already in the archive or being uploaded, then the best is chosen IIRC.
Not about the upload sessions themselves, but I'm wondering why my drawing of the Swedish Royal Falcon Fleet 135 yacht was uploaded into the Real Designs/Sweden and then later moved to the museum page.
I believe it's probably because the highlighting on the windows weren't standard, but I find it odd that it actually was uploaded in the first place if that is the case. I plan on resubmitting it with any necessary corrections and the new template in the next upload session.
if it is not responded on by somebody who can edit the main site, I would PM one of the admins. this was most likely an mistake, as the museum folder is actually purely for drawings that have been 'replaced' or are removed for large inaccuracy's (such as crazyhorses carrier drawings) and I personally do not think your drawing fits one of those categories, so I think it was moved by mistake during the archive resorting some time ago.