I agree with your assessments. I think you can get by with just one Android permission: INTERNET. The fact remains that an oscP5 message sent by the desktop never gets into the Android device while a message does go in the other direction, from the Android device to the desktop. It appears that the Android firewall is suspect, but I’m unable to figure out how to open it up. And I agree with your observations about the Processing console logs; I saw the same thing. I wish I could be of more help; I’ve spent a lot of time on this and seem to always come up short, similar to my experiences with oscP5 in the past. I remember it as being very frustrating to work with. There is also a UDP library, but have no experience using it.
Addendum:
Good idea on the changes to oscEvent() to filter out the app talking to itself.