Finally, very excitingly submitted my 4 new games to App Store. Surprisingly the status all changed to "Invalid binary" and received an email saying "Improper Advertising Identifier [IDFA] Usage".
Ok, I have to admit I got no idea what the hell is that, so I just answered "NO". Obviously Apple doesn't like that answer....
Did some research on the net and temporarily removed "AdSupport" framework as instructed. Found that it's Google AdMob that's the culprit.
Checked Flurry and AdMob but both doesn't have any updated SDK recently. So I just changed the status in iTunes Connect to ready for binary upload again, this time it automatically selected "YES" for the IDFA question. Ticked the 2 boxes which I think should be relevant and then it works!
Then as shown below, the status is now "Waiting for Review" for all 4 of them. Let's wait and see how long it's going to take this time.