The only other thing I could think of is to disconnect the battery to clear any memory still being held. I tried this once on a sync II system installed on a 2013 Edge after master reset didn't solve the problem of the system not recognizing my iPhone. If you do this remember the learning that the transmission has done will be lost and there may be other functions that will need to be relearned.
On the Apple side, delete the app, then sync with i-Tunes then reinstall the app.
On the Apple side, delete the app, then sync with i-Tunes then reinstall the app.