None of what you said has anything to do with Friday prayers in school - highschool children get into debates on all sorts of things that teachers have to step in on, and calm people down. Racism, religion, fashion, music and food choices, appearance and health, etc. 
I'm telling you this as who spent five years in a major Peel region high school, and Friday prayers have been going on now for over 20 years with ZERO objections. 

No one has any evidence that Friday prayers are unethical or illegal (it's quite contrary). No one can show that it is unreasonable, or that it's costing any taxpayer money, or that's having any impact on student learning. 

The only reason its becoming a problem now is because a small minority of hateful people have decided to make it an issue simply because they hate Muslims. 

There is no other reason. 

And their bigotry and hatred will actively and vigorously be countered by all responsible members of society, plain and simple.