CDC changed guidance for student spacing from 6 feet apart to 3. I guess they think that'll be enough. I did see some reference to outdoor classrooms. Dunno. The emails were just a very high overview.
According to the latest emails, Fairfax County Public Schools is doing a full five days in person for everyone next school year, with only limited students allowed to opt out (with properly documented health issues). Those students will have their own online classes, so it won't be concurrent, I guess.