Like Ben said, the touch ID is linked to the logic board. The only way of getting it back or a new one is to go to apple store and have them repair so they can link the two components together with their software. otherwise the iphone wont have a Touch ID as you said.

Did you try with more than 1 original Apple cable? if not try another. Try clean the port with rubbing alcohol. I noticed you said you changed the battery and it still only have 3 hours of battery ? that sounds weird to me, more weird than the charging problem. To understand the lightning cable real fast I need to explain something. The tip of the lightning cable actually has a small chip inside of it that talks to the charging port and asks permission to charge or not to charge. So I dont think it is the cables fault. I have used many off brand cables on my iPhone without any issue. So I think it has something to do with the component. Take it apart and put it back together

did you try to hard reset it when turning it on ? by holding down the power button and home button ?

Hey! . First of all, it is possible, not easy but possible. Now the reason why you are told it is not possible is because they are fused together. Fused together basically means that LCD and Digitizer is glued together. There are other devices out there on the market that does the same thing ( Samsung ). So the reason why repair centers say they cant do it ( including the one I'm working in) is because it is really really REALLY HARD. The reason for it for being hard is because you have to heat the digitizer up so you can separate it from the LCD. The easiest route to go on this is to buy an assembly set from either ebay or Amazon. When it comes to the guide, simply heat up the edges of the screen take the screen off just like you would on an ipad air. Be careful in the button right hand corner because your connectors are down there and you dont want to rip the connectors apart. so tilt the screen out, take the screws out replace the screen and BUM BUM new screen.

Hey :) did you try put the "new" screen on to see if you can get it on ?

first of all next time this happens. Turn it off. Tear it apart. let everything dry for a few days, Naturally. NOT WITH A HAIRDRYER!. This might save the phone. Now what you can try is turn it off and let it dry, get a screen and do a screen replacement. A few months ago an employee of mine came to me with his mothers phone that she dropped in the toilet. We let it dry for 2 weeks, I did a screen repair and everything works on it just fine.