BuddyPress.org

I’ve been playing with this and I too am struggling. What I have discovered is as follows:

Remove the & from the beginning of the string and alphabetical will work.
Start the string with another option beginning with an & and alphabetical will work.

Exclude does not seem to work in any variation.

I’ve raised this in a track ticket:

https://buddypress.trac.wordpress.org/ticket/7742