I suspect that there won't be any movement on the two non-main drafts, and once that work is done, this might become relevant.

I've updated this based on some discussion yesterday about the various use cases we are trying to cover.

This is far from the only way to solve this problem, and I don't claim that it is the best way, but I believe that it is likely the simplest way that meets all the requirements. In the interest of having a coherent proposal, I think it's worth merging.