So following up on possible cause that @Jeremy Thompson had shown me, I performed my typical migration - got my zillion errors - then ran a SELECT * on my Logs table after the migration had completed.

Lo and behold: There are logs from my migration

It appears the problem is that I created a custom logging provider that is dependent on this logs table. When the EF Migration runs, it is pushing logs that are picked up by my logger, which then attempts to save them to my Logs table (which is in the process of being created).

On my quest to debug this issue, I've seen other commenters in other threads recommend that your ApplicationDBContext should not live inside your app's project, but instead live in a different one. This happened to be side-effect of making that mistake. Cheers to everyone who put that out onto the web :)