I want to include HQM in a pack I plan to (exclusively) publish on Modrinth, where this mod has not been published. As far as my understanding of the LGPL goes, I could e.g. include it as an override (I want to avoid directing users to different sites), but not 100% sure this is covered by the licence, or if not, if you would approve.

So I'm asking if you would endorse this procedure, either in general or in this particular case.

The license does allow the usage on other sites than curseforge. The owner of HQM has not yet allowed us to publish it to Modrinth directly.
You can use it in a Modrinth modpack without any problems, it also does not matter, how you include it. A download from curseforge would be preferred tho