Front with collar up
The pattern would have you use a snap on the collar, with a button sewn over it, and the two layers of the collar tacked together. I made three buttonholes instead, but the way the collar sits here is essentially the same. The button goes through the one buttonhole on the left collar and then the two on the right collar.
Front with collar down
Here the collar button goes through only one buttonhole, on the right collar.
Front open, with both sides of collar down
With the three buttonholes, the collar can also be left half-up when the coat is open (which I think looks odd, but YMMV).
If the coat had been made with the snap arrangement as directed, both sides would be permanently in the folded position. IMO, if the collar were made in that way and the coat were to be worn open much of the time, it might look better with a stiffer interfacing than the fusible weft I used.
Side back with collar up
Here you can see that (because the CB pleat tapers rather than being straight) the hem is cut on a slight curve in back. If you didn't mind the coat dipping slightly lower at CB, the hem could be cut straight across instead.
Pinning to keep plaid matched in the neighborhood of the CB pleat stitching line
Laying the coat out flat shows that it's very loose below the shoulder area.
This and the following photo shows the first lining I made, which was too short (my mistake). I later took it out and replaced it with a correctly-cut lining.
Inside of coat, with collar flipped up (you see the upper collar here, i.e. the side that is visible when worn)
Underside of collar and top of outside of jacket; the top edge of the collar can flip down and button to the button seen here, to look like the envelope pic.
The re-cut lining with the intended length -- much better.