I have a late 2013 Macbook Pro with both the Intel Iris Pro integrated graphics and the NVidia Geforce 750M dedicated GPU. I run two 4k displays, one at 60Hz through a thunderbolt bolt and one at 30Hz through HDMI. I have one open thunderbolt port, and would like to add a 3rd external display. I know that it is possible to run three external displays from this model (see here, here), but I also know that it is not possible to run three 4k displays (see here).
Is it possible to run three external displays, one at 4k/60hz, one at 4k/30Hz, and one at some other resolution/refresh-rate? If so, what is the max resolution/refresh supported for the third monitor?