Dependent's 1099 DIV + earning income = filing a return?

Hello,

 

My 19 year old daughter (full time student) received a 1099-DIV of $672.00 and also had earned income (W-2) of $4473.00.   My understanding is that she would be required to file a tax return because the sum of her earned income plus $400 is less than the amount of her combined unearned and earned income.  Is this correct?

 

I'd also like to verify that my other child, who also received a 1099-DIV in the same amount but with no earned income, would not have to file a return and I would not be required to include this income in my own return.

 

Thanks in advance for your guidance!