I can probably shed some light on 2). Mopub ad stats are delayed, so you may need to wait for a day or so. As for the demo ad showing up, it could be due to the fact that no networks are linked to a particular banner. For each banner you create, you have to manually enable the networks buy entering the CPM values other than 0. This can be done in the Network Tab, in Segments->Global Segment ( or other segment if you created some more ).