That is a lot of climbing for such a short distance. I get about 1500 feet per 50 miles on some of my longer rides.
If you need waterproof, there are a few that are waterproof.
Ortlieb, Axiom, and a few others. My Axiom panniers have a drawstring and cover, and seems to be doing well. No pockets.
Most of the waterproof ones have either a heavy PVC fabric, or a waterproof laminated cordura fabric. Some are not waterproof, but come with waterproof covers.
Mine snap over the rack rails, then have a twist lock to hold them in place.
One thing, I do have a pannier set with a trunk box that can hold several frozen pizza boxes (although I've also tied the pizzas onto the rack in good weather).
Hunt for a rack that the rear-end sticks out a bit to give rear support for your panniers. I like to get my panniers mounted so that they are clear of the rear triangle to prevent heel-strike.
I'm not sure of the best rear rack. I've used aluminum racks for some. Going to start welding or brazing up a tubular steel rack shortly. One rack I have looks like an ordinary bike rack, but has a clip top for small items.
Do you use fenders or not? I tend to ride fenderless (despite the rain), and like racks with a strip above the tire to both act as a pseudo fender, as well as preventing stuff from falling onto the tire.