Perspective from the trenches: I teach at a university that uses Canvas. We are in our final exams period right now. We got our first email (from Academic Affairs) notifying us that it was down at 5:17pm EDT this afternoon, with little info; followup emails were sent at 6:24 and 6:57 with more info, but mostly about how we would be compensating for it and not about what actually was going on (other than, "nationwide…
Maybe a hybrid approach. Scramble to create a final exam/project and give them the option to do pass/fail or a real grade, their choice. And then wish for the death of saas and a day where you can deploy your own software you can control and modify as you need.
Canvas is mostly FOSS