Your policy says that if a student tests POSITIVE then they need to be excluded per DSHS rules.
If they're symptomatic, thy need to be tested to check if they are excluded.
They need to be cleared by a physician to come back to band or athletics after a positive test because there are KNOWN complications with C19 that affect otherwise healthy children.
This is CYA language on behalf of your board and district. If a kid has been sick and develops heart or long term breathing trouble, the doctor needs to clear them to participate. That seems a reasonable expectation.