I have a carbon steel knife a buddy of mine made, has lasted 10+ years. Holds a decent edge, so I can even shave my arm hair with it when it’s freshly sharpened.

Also have some cheap ass Kiwi brand paring knives made from kind of extremely soft stainless steel. Very easy to sharpen. They get used as steak knives, for cutting cheese, apples, etc.

Yes, it’s used to make oilcloth but as far as I know, you’d have to leave the garment to dry somewhere with ventilation for a week or more. However I’ve not done it so if that isn’t the case please correct me.

A cheap solution is to wax some thrift store or old trousers. Beeswax and paraffin, there are different ratios to experiment with, and premade bars you can buy. You rub some on and heat with a hair dryer or clothes iron (with parchment paper so the iron doesn’t get wax on it). It’ll darken the cloth. The more you put on the more waterproof and wind-resistant it’ll get. For bike pants you could focus on the front of the upper thigh and coat the rest less, leaving some breathability on the back.