*** Threads on I-485 and accompanying docs merged together. Please keep further questions confined to this thread only ***
If you married within the 90 days, then no.
Certified copy is issued by the county, it’s basically an official marriage certificate copy. However, you only need a photocopy of the marriage certificate for I-485.
It’s not required as at this point you don’t have much but I personally think including some if you have would be beneficial.
1. No 2. Most recent 3. That would reduce the chances of an RFE so I would include that.
Just the DS-3025 copy.
Not quick at all. Definitely file beforehand