Does it take proper charging voltage? If yes it's most probably a faulty NAND or NAND Power line. But as your customer said it was plugged in immediately points to Tristar so i would first take a look at the charging circuit. Do let me know what do you find, It would be easier if you had an ICC pro. It would’ve told you if its a tristar fault without opening the iPad.
Rice wont do any good to your water damaged phone. You can try your DFU restores but I suspect that its the Display itself or the Board because you said it has a cracked back water might have seeped in through the back damaging touch function. I suggest you take it in a reputed repair store and let the take a look. I’m sure it’s not that a big issue if they have the right tools to figure it out!
Well with a bit of common sense, you will realize its not the Charging IC itself that has gone bad. It is some other small component on the charging IC line that is causing it to heat up. If you have a thermal camera its the best time to put it to use and find that bad cap.
You’ll need to open the device to remove the camera as when you remove the glass it may damage the lens itself and it will cost you a bomb. So its better to open the phone entirely and change the lens. Hope that helps :)
Seems like you knocked off some important baseband related caps, you need to install them and also you knocked off the homer ic which controls vibration. You need to reball that and fix that too. Hope this helps :D
Hey there, this is a common issue on iPhone X and above models when the housing is replaced or the back glass is changed or the earpiece is changed or the power button strip. Would you be able to provide me with the Panic Log so I can check it and probably pinpoint the issue? You will find Panic Logs in Settings -> Privacy -> Analytics & Improvements -> Analytics Data -> and Search for panic-full-xxxx-xxxx.ips and attach screenshots of the latest available panic log. Cheers!