Imagine a lot of touching, temperature, pain spreading every where on the skin. if every sensory neural required isolated channel it might difficult to repair damaged neural because every neural must reconnect to where it belong. However, if neural act like signal cable. So each neural encode it position to the signal so it can be decoded later. It should be efficient and robust that way. If such a mechanism exist please explain how it works.
No, peripheral nerve fibers transmit just from the receptor they connect to. There is a lot of information to transmit in each of those channels: the firing rate and/or timing of action potentials constantly communicates the state of that receptor, active or not both are informative.
Yes, this means it's difficult to repair neural damage. Think about people with spinal cord injuries that have permanent loss of sensation and/or motor control.