It should work. HDMI is not in any way affected by Mac o Win environment. Just see to that you set the right resolutions for the Intesity card in capture card properties of Resolume. I have tried with both Intesity Shuttle USB 3.0 and UltraStudio Mini Recorder with Thunderbolt, and it works fine for me, both with a camera and with another PC. Wether the HDMI signal comes from a Mac or a PC, should not make any difference. Most computer resolutions over HDMI is progressive though, i.e. 1280x720p 60Hz or 1920x180p 60Hz, when most cameras output 1920x1080i 50Hz wich demands deinterlacing to be active.
I just ran Resolume -> Resolume over HDMI over the weekend. It worked great. My Intensity Pro even sent out EDID info. I would suggest letting your computer that is running Resolume do any scaling if needed.