I was convicted of six felony counts in the same proceeding in 1989. Later I was able to get the convictions expunged. I listed all of this on my application. I brought an original order of expungement signed and sealed by the judge with me to the interview.
I was not even asked about it at my interview. Part of this I am told is how the FBI or rather their database has you listed. If the FBI gets a record of the dismissal of your case then your arrest record is fine. If they get a record of your expungement and they decide to accept it (they do not have to accept it) then you are fine. I think the key to all of this is how well your state or local jurisdiction handle records of dismissals, expungements and pardons and getting them sent in to the FBI. As I said I listed what I had and was not even asked about it at the interview. I have been travelling internationally about 1-1/2 times a year for the last 18 years without any issues with customs after a few checks after 9/11. When travelling on United's first class and with United Premier Access product I had been given TSA Precheck each time I had to go through security in the year before I applied for GE.
I absolutely recommend not lying and not forgetting anything no matter how little on your application. Bring every relevant piece of paperwork that you still have with you.