This doesn't have anything to do with the water proof/resistant issue, but here's a solution for the keeping warm part.

Having a bad back, I put a ThermaCare heat wrap on one cold morning on the Columbia and to my surprise if kept me nice and warm for the several hours I was in a boat. They claim the heat will last up to 16 hours.

Almost all quote waterproof jackets will eventually start soaking water. I was photographing rain gear for the Fenwick catalog several years ago and it shed water so well I could have duck taped the pants to a pair of rubber knee boots and waded in the river up to the zipper. After five or six years they just soaked the water up. I was somewhat able to get them back to shedding rain drops by using a treatment that you run them in the washing machine and air drying them.

The are not nearly as comfortable but my 40 year old Helley Hanson rubber gear sheds water like the day I first used it, which I seldom do because I usually use the newer and lighter clothing.