Hi, I have no experience in education so this point may be irrevelant.
Why can't the Grade 11 and Grade 12 teachers be utilized in the beginning?
In this way 2 classrooms could be utilized to increase social distancing instead of 40 pupils in one classroom. The 2 sets of teachers could rotate between the classes so that both are taught by the Grade 11 and Grade 12 teachers for each subject.
The same applies to the Grade 7 classes.
This would obviously only be a temporary solution, but could maybe assist in te re - opening while the situation is being monitored.