Yes you have that correct:
1. Because she is self supporting, she cannot be your dependent.
2. Because she meets all the qualifying child rules, except the self support rule (she is a fulltime student, under 24, living at home), you can claim her for EIC (non-dependent - EIC/dependent care only).
3. Since she cannot be claimed as a dependent, she can file independent and claim the stimulus (there is nowhere on her form that she indicates that some one is claiming her for EIC only). She does not check the box saying that someone can claim her as a dependent.
