Those grates look ready to go now, mine almost always look just like that. A hot fire, a good brushing and some oil and your ready to go. It's hot and dry where I live so I don't ever store mine out of the grill. I get a little rust just like those it it doesn't bother me but others I know don't like it.
The warming rack is extremely handy, I use it all kinds of ways. I put corn on it a lot or use it to roast peppers. When I'm doing skin on chicken I start with all burners on and get a good char going then turn the back burner off and load up the rack to finish them off or hold temps. Lots of uses for the warming rack.
I hate the lid rack, in my opinion it's worthless.