The pictures need to be taken from much closer to see the state of the plants.

We also need to know where you are - zone, state, nearest big city - and how your weather has been. When were they planted?

weed free lawn ... was it sprayed?

ken

Looks like the situation in the post about the viburnum hedge where the poster got told almost immediately afterward by USDA Extension or similar source (that samples were apparently sent to) that it was honey fungus. In addition lilacs have been said by other sources to be particularly prone to honey fungus.