First plant looks like garlic mustard - very invasive, non-native plant.

Manfreda. You can post two photos on the same thread but you will have to go the the next Follow-up to upload your second picture.

Looks alittle like like malay apple.

Someone is trying to grow in the same garden two plants with opposite cultural requirements. It simply can't work. Either Sedum, sorry Hylotelephium, or Ligularia has to suffer. Looks like this time it is Hylotelephium.The insects, whatever they are, are only the symptom not the cause of the problem. My advice is: move the Hylotelephium to another, sunny and DRY location with a sandy soil, it will recover by itself. Or, if it is not possible, just get rid of it.