Can I customize the QAP icon in the Notification zone?

Yes, in Options, Launch Advanced Options tab, select the file (.ico, .dll or .exe) and the icon position (index) in this file. For example:

C:\MyFolder\MyIcon.ico,1

You can build .ICO file from your own images (PNG or JPG files) using your image editor or free web tools like http://www.iconverticons.com/online/.