Probably not. This bug?:
https://bugzilla.redhat.com/show_bug.cgi?id=1364332
Obviously the above bug would need fixing.
Yes that's it.
But I found that hard limits are correcly set, so you should only do:
ulimit -r <priority> -l <locked mem>
and start jackd from the command line
Then you can still use qjackctl which connects to the running jackd.