My child student 19 had income of 12,648 in which 10K was PUA. Does she need to file when the 10k excluded would leave her below the min 12,400 for mandatory filing?

Yes, she needs to file.  Unemployment is "unearned income".  As such the filing requirement is only $1100. 

You do not report his/her income on your return. If it has to be reported, at all, it goes on his own return. If your dependent child is under age 19 (or under 24 if a full time student), he or she must file a tax return for 2020 if he had any of the following:

1.          Total income (wages, salaries, taxable scholarship etc.) of more than $12,400 (2020).
2.          Unearned income (interest, dividends, capital gains, unemployment) of more than $1100.
3.          Unearned income over $350 and gross income of more than $1100
4.          Household employee income (e.g. baby sitting, lawn mowing) over $2100 ($12,400 if under age 18)
5.          Other self employment income over $432, including money on a form 1099-NEC

Even if he had less, he is allowed to file if he needs to get back income tax withholding. He cannot get back social security or Medicare tax withholding.

In TurboTax, he indicates that somebody else can claim him as a dependent, at the personal information section.