A child wrongs a stranger: the family apologizes, or the child alone?

Both, really. The family apologizes as the primary guardians, then the child reinforces it themselves when they're ready. Not either/or.

The child alone. They did it, they face it. That's how people grow up.

Family apology signals shared responsibility and teaches the kid they're part of a unit with consequences.

Depends on the age honestly. Toddler? Family handles it. Teenager? They should apologize themselves.

If the child can't apologize themselves, they haven't learned anything. The family backing them up is one thing, but the child needs to own it.