You do need layers. Over the last couple-three years I’ve added the short working mans coat to my kit. Just to trousers tops or a little lower made with an upright collar after the 1790s or so sans collar before. Definitely helps when added to a good shirt and maybe weskit below.
You can make your capote from a blanket but if you get about four yards of a heavy blanketing you can make both coats matching.
It’s good to add a lining to your capote, I like a lighter wool. Should you go with a Taylor’s coat the better fit is easier to move in and more comfortable and I think pound for pound warmer then a loose style capote.