Iwobi wasn't very good the other day, but he looked quite good in the Emirates Cup when surrounded by better players. Campbell is sure to start tomorrow though, so let's see how he does. I wouldn't rule out trying Iwobi if Campbell stinks the place up though.
For the Bayern game midweek I think Wenger will go with Gibbs for the added defensive protection. With Giroud leading the line from the start, I'd say our best chance in that game is to try to defend for our lives and hope for a 0-0. Possibly a set piece goal.