We are just gathering the I-864 documentation.. Can stuff like birth certificates, etc.. for the co-sponsor be photocopies ?

Yes, but the originals must be available to show the Officer at the interview.

For co sponsor a copy (photocopy) of the US citizenship or permanent resident will be required.

http://www.uscis.gov/graphics/formsfee/forms/files/I-864.pdf


If you are a joint sponsor, substitute sponsor, or the relative of an employment-based immigrant requiring an affidavitof support, proof of your citizenship status, U.S. national status or lawful permanent resident status.
For U.S. citizens or nationals, a copy of your birth certificate, passport, or certificate of naturalization or citizenship.
For lawful permanent residents, a copy of both sides of your Form I-551, Permanent Resident Card.

joej,

Correct - a copy can be submitted with the I-864.

But raymaga is also correct - an immigration or consular officer has the authority to ask to see the original in order to verify the copy. So it is wise to have the original on hand in an interview situation should the request be made.

Yodrak