If the Ardour package doesn't work out of the box, I think the place to start is filing a bug (or bugs) against it.
I'm no expert on PulseAudio (my only advice is that in Xfce, you MUST install https://apps.fedoraproject.org/packages/pavucontrol), and I know nothing about Jack, but I bet there are plenty of Fedora users out there who have experience and tips to share on Ardour.