Doesn't exist. Get a a good rain coat and pullover rain pants. Alternatively there's some good cycling specific ponchos.
Bike should have chain guard and long fenders to keep your ass and back dry and with mud flaps to keep your feet dry(ish). Might be a good idea to use rain boots and keep shoes in a bag if it's raining.
I use a cycling poncho, fenders, and chain guard. I only ride about 3 miles, but even in the worst weather I only get wet from about mid-shin down, and even then only enough to be bothersome in the worst weather.
I definitely miss not having chain guard and fenders with Seattle weather, but have switched over to a raincoat and boots for biking. Waterproofing the commute is totally worth it.
In my experience soft shell is neither very breathable nor very water resistant. It's both, but as with GoreTex it's a compromise. Nothing that is 100% water resistant can be breathable and vice versa. GoreTex is very water resistant but not very breathable. soft shell is pretty breathable but less water resistant.
Technology might have improved since I bought my last soft shell pant, though.
Bike should have chain guard and long fenders to keep your ass and back dry and with mud flaps to keep your feet dry(ish). Might be a good idea to use rain boots and keep shoes in a bag if it's raining.