Generally elsewhere in the world you can stay airside, but the US might be different. If you get a mobile BP no need to do anything, just rock up at the gate. If EK Has its own lounge at IAD They can also print a BP. Once you do OLCI you can basically even ask the gate for a BP reprint.
​​​​​​I virtually always travel with a rollaboard and Laptop bag in Y without issue, worst case they gate check a bag.