Those green bars are crop marks, they will not show on your stream, but will define the area of the desktop that is being captured. You can get rid of them by pressing the 'Zoom out' button on the Procaster HUD a few times until they leave the screen area. If you want to hide the HUD and mixer window, you can use the 'Minimize' option at the far right of the HUD.
When selecting 'Headphone Monitor' in the audio mixer, are you not able to hear the audio you're outputting? You should make sure nothing is muted and the correct audio source is selected. The message you receive is a Procaster bug, which can be ignored.