Unfortunately the OSM website has a limit to how many it can show you at once and it shows the most recently updated ones, so you can’t see how many unclosed notes still exist.
One of them is over five years old and requires on-site verification, so I know what I’m doing this weekend!
You can do that, from Notes Review FAQ, question mark on the top right corner:
Is it possible to exclude certain users?
Yes, by writing either NOT or - in front of the user to exclude. It is also possible to exclude multiple users by separating each user with a comma.
I did try using a - in front of the user name, but their notes still showed up. :/