I had to remove FAdmin for ULX to work, and without FAdmin I cannot blacklist people.
That's very strange, I have seen many servers run ULX and FAdmin together without any problems, what happens when you try to run them together do you get any errors?
Also it would be possible to make a plugin for blacklisting people from jobs/teams.
Just have a script check what team or job a person is trying to change to and if they are banned from that job or team it would do nothing instead. (You would need a file to store your job/team bans.)