Battery Problem, possible motherboard damage ?

Hi all

I have had my nexus 5 for a while now and just as i was flying overseas some strange things happened.

First the vibration stopped working which i knew was a loose connection on the back of the phone. Holding that area down would get it working again. Then the touch display stopped working. The LCD worked but could not touch anything to unlock the phone. I disassembled the phone and assembled it again and strangely it worked again although i didnt see anything obvious. Then is happened again...

I disassembled the phone and played around with it for a while and noticed if pressed down on the connection where the flex cable connects to the motherboard it would work again. but when i would release the pressure it would be funny again. I did this a number of times until eventually the whole LCD/blacklight should shut off. Now i can rarely get it to display anything. The phone is working because the LED light would flash and i can hear the messaged coming through. I just cannot see anything.

I replaced the flex cable with a new one and still the same issue. I replaced the LCD + digitizer + frame and still the same issue. I guess its the motherboard. Can i fix this ??

Now for some more issues:
I bought a broken Nexus 5 while overseas and i swapped the motherboard out and everything works! So it as definitely the motherboard. However, the second motherboard is having issued the the battery. I have every indication the battery is charging. However the battery percentages is stuck on 40%. It would flicker around 39% 40% instantly and when looking at the battery graph on the phone it is noisy, it is not a constant line. The percentage is not a true indication of the battery charge. I cannot get the phone to turn on just by the battery itself no matter how long i charge it for. I have swapped batteries out and i still get the same issue. I have swapped flex cables and still the same issue. Could it be that the second motherboard is also damaged??
I used the amphere app for a while while i had some power and it shows 50mA while charging but a voltage of 0V! When I unplug the cable it will shutoff. Sometimes i cannot even boot it up while charging.
What is wrong with these two motherboards?! I do not see anything obvious on the board itself.
I now see the new Nexus 5X is out but i am hesitant in buying it...This is the first phone i have had major issues with.

PS, i gave the latest updated

Thanks for your help guys. I will provide whatever information i can.

Dual camera won't focus, makes crackling sound (water damage?)

Last Tuesday my phone got wet while on a bicycle ride where it started to rain. The phone got wet enough that it started to randomly jump to different screens. I turned it off and put it in my pocket. Once I got home and dried the phone it seemed fine, and in fact the next day used the dual cameras to take a pic with no problem. There seems to be no water damge indicator in the dual flash.

Today tried to take a picture using the dual cameras and immediately got this crackling sound and the cameras wouldn't focus. I've done a search and couldn't find this exact problem elsewhere. The best way to understand what the cameras are doing is to show a video taken with them:

https://youtu.be/rms54f8O4vA

You can both see the inability of the cameras to focus and hear the crackling sound they make while trying to focus.

If I shift to the front facing camera it works just fine.

What to do? are the dual cameras kaput? :(