As a parent, it's time consuming and not always easy to keep kids focused on tasks with all the distractions of home. We do now have some sort of a routine that seems to be working.
As a teacher, we have the same few who are doing everything that is asked of them. For some I've seen no evidence of any school work done since we have broken up. My school's approach has eased up a bit since Easter to take the pressure off everyone. We have a table of activities that they can choose from now rather than setting a timetable of activities. I seem to be getting less messages from stressed parents so that is a good thing for all involved.
To answer the original question, when I was in school recently there was no social distancing between the kids or the kids and adults. That was with 8 kids. I don't think it would be possible to enforce even if you only had 25% of a class in. The corridors and classrooms make it a physical impossibility not to mention the fact that kids will not stay more than 2cm apart let alone metres.