My suggestion is: For everything that depends on AUCTeX, prefix it with
auctex-, and for others which work with built-in mode as well, take tex-
as prefix. Rationale: it makes things easier to find once you do 'M-x
list-packages RET'.

Copy. So maybe "auctex-numbering" (or "auctex-latex-numbering"?) and "auctex-latexmk-continuous"? (unless these are considered suitable for upstreaming, in which case the point is moot)

>> I'd be happy with whatever makes the most sense, but figured submitting to
>> ELPA would make them readily available without introducing additional
>> burden on the AUCTeX maintainers.
>
> I'll let the AUCTeX maintainers decide. That being said, I am sure
> they'd always appreciate a helping hand in general.

Disussion about upstreaming parts of Paul's code would be the next step,
I think, based on user feedback and request.

Let me know what, if anything, I should do to help with this.

Reg. helping hands: Always
welcome, but I really wish that people take over which actually use
LaTeX/AUCTeX/RefTeX on a regular basis. I can tell for Tassilo and
myself that we don't use LaTeX anymore, and that for many years now.

I qualify as a long-time daily user of latex/auctex (and until fairly recently, reftex), but am ignorant of tex more broadly. Happy to help how I can.

(I tried to help as far as I could).

(Thanks again!)