Looks good, it's super helpful to have this written down in one place. I left a few questions on the github PR, the only substantive one is really how to target the intro for the audience, given that this might have to serve multiple different audiences.
One other thought I had while reading this in detail is that the wings of bright stars might cause problems with making usable cells for coadds (the wings might be affecting a larger area than you can make into a single cell). Presumably the first-level answer is to use Gaia to avoid having to fit the bright stars at all, but I'd worry a little bit about whether there are stars too faint for Gaia photometry but still bright enough to cause problematically large wings. This might be a more detailed question than this writeup really needs to handle, but we'll need to figure it out at some point.