Related to this, I want to put in details of how instance blocking and lack of federation work.
Important questions that I don't know the answer to. assume in all of these that I am on instance A and instance be has been blocked by instance A:
1) Can I still follow someone on instance B?
2) will I see a message from a user on instance if they @ me?
3) what happens if I am following someone on instance B when it is blocked?