I've not seen any 1060 locked to a single monitor, it's usually a minimum of 2 on some 3rd party OEM, hdmi and dvi-d dual link. The normal 3rd option being vga and capped/locked.
Yes, you can tell the bios to use multiple monitors, even windows/nvidia control panel had a multiple monitors switch that'll allow usage of motherboard headers, just be aware that any monitor hooked to the motherboard will be igpu only, it'll not be linked to the 1060, so don't expect miricles.