Yes, if she is required to file, she would need to file a separate return. Yes, you can claim her as a dependent. You will need to indicate this on both returns.
Single dependents
You must file a return if any of the following apply.
1. Your unearned income was more than $1,100.
2. Your earned income was more than $12,200.
3. Your gross income was more than the larger of— a. $1,100, or b. Your earned income (up to $11,850) plus $350.
