I have Samsung Note 4 that has water related damage, which has resulted in distorted audio from the loudspeaker, the ear...

As others mentioned you need to replace the LCD Screen and Digitizer which come as an assembly. I would not recommend trying to replace one without the other. TIP: If you just need to access the phone. You can connect a regular USB mouse with an OTG cable. Also if you have the opposite problem (where the touchscreen works, but you can see it), you can use a SlimPort to HDMI adapter to see the screen on a monitor. I don't think you can use both an OTG and SlimPort at the same time.