The primary question I’ve had regarding the Linux version of Bitwig Studio has been answered. It does support Jack. You can see this answer, and get more information on the FAQs page at the Bitwig Studio site.
I’m not a part of the beta, as far as I know, but as I learn more, I will attempt to post here. Considering that this is not an open-source tool, it won’t be the highest priority, but it is a tool available for Linux and it has Jack support, so it deserves some mad respect.