Can You Build a Working iPhone From AliExpress...? (youtube.com)
The camera is actually hard to find not made by Apple, so when you buy a non-Apple one, it's usually just they cover the Apple log with stickers. Most of the parts are like this. It's hard to find a good quality screen on Ali. I guess one thing about fabricating your product in China is you can't control people selling parts. Apple has a screwchart online, and that's useful because you have to have the correct screw length.
$350usd, half the price of refurbished.
The waterproofing, water enters the hole for the speaker and goes into the speaker but not further.