The lining went in relatively easily. Betzina's instructions have you doing the normal "right sides together, sew the lining to the facing" routine, leaving the bottom open. Okay. Then you pin the sleeve hems to the sleeves and pull them inside out (this is supposed to keep the sleeve from twisting when you sew the lining to the sleeve hem - actually, it still twists, but so long as you do untwist it prior to turning it right side out, you'll be fine. If you don't, then your sleeve will be right and the lining will be twisted up. Ask me how I know.) The sleeves get pulled out through the bottom of the lining and sewn, hems together. Then the whole coat gets folded up like a leather burrito and the lining hem gets stitched to the garment hem. I did end up using interfacing along the hem of the lining so that it didn't rip when I turned it right side out. I also sewed a strip of black hem binding to the very top of the jacket hem so that if I couldn't manage to get the last bit of lining attached to the leather, I could slipstitch it to the fabric binding. One of those lightbulb moments. Combination of lining fabric to leather was a little weird, mainly because the leather needle kept snagging the lining fabric, but when I tried a finer needle, it snapped. So there are a few picks in the lining and I will have to live with that.
There will be a full recap of the project soon, once this has had time to digest in my mind. I liked this project, I learned a lot, I entertained myself no end, and I ended up with a jacket out of it. How cool is that?