So there's a couple of bits of experience I can share that might be of use.
1) When students are using Github for summative work we insist that they create an account based on their institutional email and ID, and we have some pretty tough spats over this, but we see it as important.
2) A former colleague set up a Github process whereby the students were tasked to work through a series of tasks in their own Github instance based on his application and content. Because we require submitted work to be on Canvas, his application then spat out the evidence of the students work, personalised to their identity, for upload into Canvas. Unfortunately he's gone back to industry and the approach with him.