iFixit also confirms that the new phone's battery is a bit bigger than the one in 6s plus (2900 mAh vs. 2750 mAh), which supports Apple's claim that it can last an hour longer. As you can see above, the device's dual rear camera comes as a single module. It lives in the bigger exterior bump that's now apparently built into the chassis itself as a water- and dust-proofing measure. You can follow the team as they dig into the the phone's innards further. But if you're more interested in what's inside the Apple Watch Series 2, you can also keep an eye out for its teardown right here.
Update: The team is almost done. Besides a more waterproof camera nook, they also discovered that this model's Lightning connector is protected by a full-on rubber gasket to prevent water from getting in. In fact, the whole phone has a whole lot of waterproofing going on. As for the new home button, iFixit was able to remove it, so yes, it is replaceable in case it ever malfunctions.