If they are supposed to be captured washers, and crush washers, that doesn't make a lot of sense. You certainly can reuse a crush washer, but not multiple times, and you should clean it up as Krash mentioned. I've even done the old heat with a MAPP gas torch trick with used ones.
But another reason they are stupid, is that the upper caliper pin bolt is in the way if you try to screw in the banjo bolt with the fitting at the head already. Ask me how I know. With regular washers, you just drop the bottom one on the caliper, set the banjo fitting down, then install the bolt with the other washer on it. I fought with the captured banjo bolt for ten minutes before I decided to pry off the washer to remove it from the fitting, and it was in in seconds.
Welp, we got back to the car yesterday afternoon. The banjo fitting that I had to file down had wept some brake fluid, so it wasn't as sealed as I'd thought. Took a finer file and had at it for a good while, and finally there was no nick or scratch that made it to the circumference of the hole. Noticed also that the two crush washers I had used before (new ones) both had an identical set of radial scratches in them. Found an old one that was all smooth and used that instead. Bled that caliper and got some air out of it, and the pedal was nice and hard.
Started it up, and with the booster working, the brakes felt tons better. Put the wheels back on, and my son took it for a test drive. All seems good now. I don't feel fully confident in that fitting I had to file down, but then again on Tuesday, the soft pedal was immediate. I'm thinking it's either leaking and not holding pressure, or it's a tight connection. He wants to drive it to Boston (3 hours away) Friday with his buddy, so I told him just drive it around town a bit last night and today, and if the pedal feels the same, he's good. If we do end up needing to replace that line, it's not the end of the world.