It definitely seems like multiple people can be involved if there is uncertainty on whether to reject the app. From experience, I've found that if my app is sitting in "In Review" status for more than a certain number of hours, it's likely to get rejected.

The only time Apple gave out hard numbers on their review setup, a couple of years ago, they had two reviewers check each submission, with an average of 6.5 minutes per reviewer per submission spent checking it. Obviously, that average contains quite a bit of variation.

that 'automated code analysis' also let a 'Flashlight' app that was, actually, a covert tethering app go live.