I did some triple topstitching on these also, just like his pants. Other than here on the front pockets, it is also on the welt pocket flaps and the hems.
I used a neutral plaid for the interior waistband. It's cut on the bias, but it's a curved piece so it doesn't end up on the true bias at the center back. Waistband closures include hooks and eyes and a button. Peter just had a great post about installing these hooks and eyes.
Finally, there are the welts and flaps on the back - no pockets. I adjusted the darts so they are parallel to the CB seam and perpendicular to the welts.