1. Here's what the I_485 instruction says about submission of Court Records (Certified Police and Court Records of Criminal Charges, Arrests, or Convictions) (as in who needs to submit):
You must submit certified police and court records for any criminal charges, arrests, or convictions you may have:
D. If you EVER had any arrest or conviction vacated, set aside, sealed, expunged, or otherwise removed from your record anywhere in the world.
In general, you do not need to submit documentation relating to traffic fines and incidents that did not involve an actual physical arrest if the penalty was only a fine of less than $500 or points on your driver’s license. However, you must submit such documentation if the traffic incident resulted in criminal charges or involved alcohol, drugs, or injury to a person or property.