It should all work. You *may* have/want to connect a USB cable from the mini to the 24" in order to get the communications going. That bug was supposedly fixed in 10.8.3 but I honestly dont recall if the DVI connection supports that directly (I think it does).
When the SV software starts up, it detects all the displays and at the bottom of its main window is a dropdown menu where you select which display you want to calibrate or work with.
I'm going to add another NEC PA (24 inch) to my current NEC PA (27 inch) which is attached to my 2012 Mac Mini quad core i7 (running Mountain Lion) with 16GB RAM which I attach via the display port to the Mini's Thunderbolt port.
The 24 inch NEC PA should attach via the DVI-D to the Mini's HDMI port via the included DVI to HDMI adapter.
Has anyone else tried this set up and does it work? The specs seem to match up in terms of supported output for the respective monitor sizes. HDMI supports 1900x1200 which matches the 24 inch while the Thunderbolt supports 2560x1600 which matches the 27 inch monitor.
Another question is with calibration. Can I calibrate the HDMI connected monitor using Spectraview II? Is there a way to tell the Mini/Spectraview software which monitor I want to calibrate?