What are the additional signatures you asked about since the taxpayer has already signed on the form, presumably?

At that point, what you need to do is to add the taxpayer's signature date on General > Electronic Filing > e-file Signature Main Form.  Your signature date as the ERO should be defaulted to the date of submission unless you have good valid reasons to override that.

You mentioned "unpaid tax preparer".  Are you with VITA?  If you're unpaid, why would you call the taxpayer a client?

Note that even if you are unpaid, F.8879 is still required for e-filing and you, as the ERO, are still required to sign with your PIN.

You may also like to refer to this older discussion about non-paid preparers: https://proconnect.intuit.com/community/lacerte-tax-discussions/discussion/7701-a-36-states-in-part-...

Thank you. It filed and was accepted as non-paid preparer. I did put in the date in e-Signature Main Form. And I did get a signed 8879, of course. 

Not sure why Intuit/ProConnect would have that option “non-paid preparer” if it would cause problems. How are people to file family members who do not pay.  This was my first return using ProConnect for a family member so I hope since it was accepted I’m all set. I do have paying clients that will be “paid preparer” and of course myself as “self-prepared”.