I think you can always request that your child be moved to a different classroom.

If the cyberbullying happens during school hours, which might be observable by time stamped posts, you can show that.

But, otherwise, the link you posted was fairly clear.

You can find the answers on the link you just posted.

https://www.stopbullying.gov/laws/index.html

Am I understanding correctly that in the commonwealth of Virginia, schools can not take action on cases of cyberbullying (through Instagram, snapchat, etc.) that occur outside of school, even if both students attend the same school? But in Maryland, schools can? In DC, they can IF the cyberbullying will impact a school activity?

I am in Virginia. So if my child (middle school) is being cyberbullied through social media, and I tell the school and show them the evidence, no consequence can come to that child through the school? Even if they can not technically punish (suspension, expulsion, etc.) the bully, can they take other actions (make sure the victim and bully are in separate classes, maybe put a note in the files so if a situation ever does occur at school, it is noted that there is a "history" between the two children?)

FWIW, this is not happening to my child right now.