5.) I'm in the process of obtaining my own fingerprinted FBI check, if no mention of a DUI shows up but an arrest does, could/should I try and get away with leaving those three letters out in an interview?
This is good information to have but beware the FBI records don't always show everything. I also got a FBI record for similar reasons and was very suprised to see the results. BTW these take about 12wks to process FYI. At any rate along with your FBI record I would also get a NDR. If you were infact suspended and there is a record of it the NDR is most likely going to be the source that points to your ticket. Especially in your case where it seems you may have received some leniency due to your age. Any airline you get hired by will require a NDR so be safe and know what is on it!