You might get sensory overload and be unable to distinguish the sounds, but the waves would not necessarily be interfering with each other enough to be noticeable.
It depends on how you are viewing the EM Radiation. For example, radio waves can be thought of as actual waves and the amplitude as a direct increase in the signal strength. However when talking of individual photons this no longer works. The energy of the photon would be E=hv, where h is Planks constant and v is the frequency.
Again, it depends on how you are looking at the light. As a wave model the light simply spreads out like any wave does and the intensity of the light drops off as distance from the emitting objects increases. In terms of photons, the Sun emits uncountable numbers of photons which then move straight out away from the Sun. The intensity drops off as distance increases because the photons spread out into space, similar to birdshot from a shotgun spreading out in the air. The energy of each photon is set and does not change and the photon does not spread out as it travels.