Thank you for contacting us. The display your were planning is correct (DisplayPort+HDMI+VGA). However, the DVI option will not be possible because our processors do not support dual link. So, I recommend you to select another board or try to get the monitor HDMI/DisplayPort.
***Another option came to my mind, it is not a recommendation, it is just something you can research a little bit more, you might consider an DVI active adaptor.***
Wait... on that FAQs I read
"What three independent display configurations are supported?
View information for the Intel® Iris™ Pro Graphics 5200, Intel® Iris™ Graphics 5100, and Intel® HD Graphics 5000/4600/4400/4200"
"Three independent displays are supported with most combinations of HDMI*, DVI, VGA, DisplayPort* (DP), Embedded DP (eDP), and Intel® Wireless Display (Intel® WiDi)."
So why is DVI listed in that FAQs if is not compatible? Also there is no sign on that FAQs that tells to use at least an adapter for DVI connection...
I think that guide is not very clear...
Were you able to get DVI active adapter? Did it work?
The minimum requirement for three monitor configuration is Display Port.