Very Quick Update: Tomorrow evening I leave for a business trip to London, and I am determined to wear Lady Grey to the airport. Right now, all that is left to do is final topstitching (the lining is in!!!), sewing the sleeve lining to the sleeve hem, and sewing on the belt loops and snaps (I decided on large snaps rather than buttons).
There are some optional finishing steps that I'll do if I get the time, like invisibly stitching the lining to the coat shell along the princess seams and sewing the lining hem to the coat hem.
Thank you to everyone who has been cheering me on with this project - your comments have really kept me going. I can't wait to show you the final pictures!