Nobody cares about Chromebooks. They only matter in schools and they're almost certainly illegal in schools, so that will self-solve when those charges get addressed.
Minors can't consent to being spied on. And being a school to which they are obligated by law to go, they can't be forced to consent even if they could consent.
There are multiple cases being processed in Denmark at the moment. While Chromebooks aren't outright illegal, Google's processing of school children's personal data might apparently violates the GDPR.