Jaybird,
Congrats on the interview; exciting times! How much time do you have before the interview? Are you located in close proximity to the unit? If so, it wouldn’t hurt to see if they allow visits beforehand. Any face time you can get before the interview may be invaluable. Also, I don’t know if you’ve perused the website, but the E-Course for interview prep is a phenomenal tool. Quick and easy words of wisdom are to be yourself, be confident, and try to have some fun.
Always go with Dress Blues unless specifically told otherwise. The hiring POC is most likely referring to any changes to your already submitted Application. Think new test scores, new Letters of Rec., updated flying hours, etc. If you don’t have any major changes, I wouldn’t worry about it.
Hope that answers some of your questions. Good luck!
-CHAOS