How can I stop applications from preventing restarts?
If you insist to not save any work, open terminal and run sudo shutdown -r now

You could force the updates as well before issuing the restart with softwareupdate -ai and never see an “Are you sure?” or “Save this data?” dialog since the shutdown command sends SIGKILL which kills as opposed to asking nicely for programs to exit. 

Back up your files, the filesystem will be safe but your data in specific files won’t necessarily be safe.