The desired end result is that the necklace is cloth-like, and the star-shaped charm is rigid. Both react realistically to the environment as they hang around the character's neck. Thus far, I can get the bare necklace to behave properly, but I do not know how to include the charm. The necklace is cloth-simulated, with pins anchored to the back of the neck.
Grouping these two items into one mesh and designating the star as a structural group gets the desired effect, but the star deforms easily with quick or strenuous movement.
I will make a .blend file available upon request.