1. I agree that the criteria of the ILO Conventions would apply, and I would try to get data on these complaints and how they compare to the minimum acceptable of the conventions. Likewise, with Proterra’s own requirements as stated. And check how the site justifies complaints.
2. Definitely Goal 5, as it is quite directly addressed by principles 5, 6 and 9; and Goal 8, given the relevance of the topic of human and labor rights.