That is not supported at this time, as we wanted to keep the initial tech preview limited in order to better address functionality. Opening up to additional controllers is likely to come in future builds.
Yes looking for support for Wirecast 8 for Launchpad Pro. Note that I see problems on Windows 10 with Launchpads hooking into USB3 so look for a USB2 port. Launchpad MK2 seemed to work well when tested. Upgraded to a Launchpad pro but not seeing support in Wirecast 8 yet for it.
Jason Phillips The developers are measuring user interest. As you can see you're the first to respond to this thread in three years. There's also this in Feature Request voting but it only has 3 votes so far.