HP Elitedesk 705-G3 Mini AMD:A10-8700E 8GB 500GB/7200

Do we know if the “1 choice of 2nd DisplayPort™ or HDMI or serial” output is included? or what it is?

Well, funny thing there. It’s can vary from unit to unit based on how it was originally configured. In other words, we really don’t know which one you’ll get.