Macbook Pro 13" Late 2016 external video support
The video card is Intel Iris Graphics 550.
The "Video Support" section of the technical specs says:
Simultaneously supports full native resolution on the built-in display at millions of colors and:
One display with 5120-by-2880 resolution at 60Hz at over a billion colors
Up to two displays with 4096-by-2304 resolution at 60Hz at over a billion colors
Does that mean it can do both simultaneously or pick one? I know this isn't a port-based limitation, it's purely how much the hardware can push.