Can VC081 emulate display (HPD)? I mean if only VC081 connected (no monitor) the computer will still detect a monitor and keep the screen configuration. 

VC081 can act as a monitor and cheat the source computer to keep as 2 monitors if the PC actually has one monitor and one VC081 connected together without the second monitor. 

For keeping a PC or Server awakened， it really depends on the graphic card's design. The result may vary.