No, lichen doesn't harm plants.

I agree, they are two separate issues. Azaleas are very shallow rooted shrubs and they love their water. The ground must be kept consistently moist. A good 2 inch layer of mulch would certainly help. They also like a slightly acidic situation. Sprinkle a couple handfuls of pine needles around the root zone. Trim off any dead wood.

The lichen is innocuous - adds a little character but nothing to worry about.

Agree, the lichen is not harming the azaleas, but excessive lichen growth on azaleas is usually a sign the plants are not doing well, may already be dying back in parts, and need some extra care. Its late in the year to feed them, but if you haven't given them any fertilizer this year at all, and given they're obviously in a poor state, its probably worth risking it, as well as gently turning the soil over around them, and adding a mulch of something like composted manure or good garden compost from your own compost heap. More info here, you'll need to copy and paste into your browser

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