>>2852874You sound like that guy who wanted a space suit for the outdoors. There's tradeoffs in very material and construction.
>Outer materialYou can go with a synthetic material with goretex membrane, that would be waterproof breathable. Not very durable though and would be damaged by sparks. Or you go with cotton like a palatka, but it would not be fully waterproof. Or you go with wool gabardine, which is durable, decently water repellent, mostly unharmed by sparks, but good luck finding or paying for it. Anything durable will be bulky.
>InsulationI suggest a climashield fill, it is light and durable. The proper weight will have to be determined by you. Insulation creates more bulk.
>LiningThis one is easy, a synthetic lining will do fine. Again, the more durable you want it, the heavier it gets.
Do consider what kind of pattern you want it to be in. A poncho is easily made, but will have a lot of excess fabric. Go with a more tailored pattern.