Hey MacRumors-Friends,
first: sorry for my bad english. I'm from Germany and i try my best.

My 7 plus had exactly those clicking noises, as in the video of iJustine. In the local Apple Store, my iPhone was replaced two times. Against a new device, no refurbished. Overall, I had three iPhone 7 Plus, all devices with the fancy clicking sound. Sometimes quieter, sometimes louder. I went a fourth time to the Apple Store. The employee said: so, that's the quality from Apple. If I'm not satisfied with it, I get my money back. They do no other replacement.
Today, I bought another iPhone 7 Plus (black, 128 GB) with Pick-up in the Apple Store. A Wonder: No noise!! Nothing! They really exist! But also on the 7 Plus test devices in the store, I've heard the clicking. Not on every Phone, because sometimes the sound is so quit, you can't hear it in a Store with so many people inside, they're talking. So, you need a lot of patience and perseverance for the replacement - or must be comfortable with the clicking. It's just luck. I'm satisfied now and can finally (!) enjoy my 7 Plus.