They can each file a return to get the federal taxes back on the W2 box 2. But it's probably a very small amount. I'm surprised they took out federal withholding. Since it's a small amount I would just give them the withholding (even the ss & Meficare) and don't bother filing a return.
To file, Online is only good for 1 return per account. But you can use the same email address for 5 accounts. How to start another return in the Online version
https://ttlc.intuit.com/community/using-turbotax/help/how-do-i-start-another-return-in-turbotax-onli...
or just fill in the blank form, should be easy.
https://www.irs.gov/pub/irs-pdf/f1040.pdf
instructions
https://www.irs.gov/pub/irs-pdf/i1040gi.pdf
