This is going to be a weird one, but. So I shared one commission of a new prospective artist under the intention to give her exposure with her blessing. And we both discovered to our surprise that one upload for example got 40x more faves than the same one she submitted to FA. So thus, she's aiming to make an account to post her content here, but she's hoping if it's possible to transfer all my present uploads she drew into her account to keep her content centralized. She has my blessing for the record, but we were wondering if there's a feature we can do so aside from having her repost a *superior* version of the upload and thus flag my submission to be deleted in the process?

If they want to repost everything they'll need to do that. If they don't have a superior version they want to make public they'll need to submit this form
https://e621.net/takedown/new
and request a CDNP of artist only posting.

These both will effect your posting limit, and in my opinion isn't really necessary. With e621 being a booru all content on the website is a collective, here is no personal galleries and the goal is simply to archive the best public versions of art. As long as the artist you are talking about is listed on the suggested artwork and their images on site are sourced properly, all the glory is still theirs anyways. If anything it's probably better for them to just upload their own content going forward if that's what they want to do, and set up their e621 artist wiki with source information and commission information

The name attached as who uploaded a post has no impact on the level of control over the post, and e6 isn't set up, or even designed to provide any control over content once it is posted, regardless of who that person is. It simply isn't one of the goals of the site, because it's not catering to be a personal gallery. The "centralized content" in this case would be their artist tag, which holds all of the posts that they are the artist for, and this is automatically managed by the site as any other tag is, regardless of who posts it here.

So just leaving it how it is, and having the artist post their own work from here on saves everyone a lot of work instead of having to deal with resolving flags on posts that are rather ambiguously "superior." In many cases, these are rejected because they are newer, but identical, and the older copies are preferred as the originals, because they can be properly publicly sourced.