I currently have a Kinect for Xbox 360 and I would like to add the Asus xTion Pro Live camera for the 2 camera option. Will this mixed type work with iPi Soft?

iPi Recorder v2 should handle this mix as both models have compatible video modes. However, we had not tested such mixed configuration, so cannot assure you for 100%. As a first thought, there may be some frame synchronization issues as different cameras internally employ different techniques to maintain capture frequency. Certainly, we recommend to use uniform configurations to avoid unexpected issues.
iPi Studio will have no problem in tracking the mixed video as soon as you can get it recorded.