Documents for DS-260 and other questions

[rubs]

Hi,

We have applied for GC for parents (currently living in India) and got approval of I-130. We recently sent I-864 and I-D864a with all supporting documents. We also filled out DS-260 online for both the parents. We have following questions:
1. Do we need to send civil document to NH(USA) or Delhi(India) as one of the documents is Photo so if we need to submit in US then do I need to get photos printed and send or parents can take with them during the interview?
2. Can we send the documents in email, if "yes" then how will submit the photo if that is required?
3. What are the civil documents needs to be submitted as some of the following documents are already submitted during I-130:
• Parent's Date of Birth
• Petitioner Date of Birth
• Parent's marriage certificate
• Police clearance certificate (this was not submitted with i130)
• 2 passport size photos
• Are we missing any other document?

4. Can they do the medical to save time or we need to wait for confirmation of approval of I-864 and DS-260?

Thanks
--Rubs