Hi Sir,
I am not sure what is the reason to cause those issues you faced. I have tested debian 8.1 with wifi dongle EDUP EP-N8508GS (chip RTL8188ucs), everything is fine, no crash at all. To connect a monitor, I use a HDMI to VGA adapter, because no HDMI on my monitor.
May I know more details about those boards? When did you get it? After you get it, you installed Debian instead of preloaded Fedora 22? After you installed debian, it will crash soon? Before it crash, what did you do? If possible, add my skype id: tim.jjune, we can talk in details.