We've had some pretty awful heat and weather here in SoCal, too, so I can sympathize! I wouldn't cut the canes on your roses unless they'll sunburning. Modern roses store the starches and sugars they need to grow in the wood. When you cut it unnecessarily, you're taking that stored food away from them prematurely. I found here (Southern California middle desert) that over head watering helps rehydrate dessicated bushes faster. They absorb it through all plant parts. A good, deep soaking, repeated at the frequency your drainage and budget dictates, helps to restore them to productivity. You don't want to feed them anything except water until you see a lot of new growth. All fertilizers are salt, or develop into the salt forms of the nutrients. Your roses are water stressed. Giving them anything salty will remove water from them at a time they can ill afford it. You can actually burn and kill them, so stick with water until you're comfortable they've recovered and are actively growing again.