As posted, Vegas is pretty hot in August. 120*F +/- a degree or two is not unheard of. You would do well to bring your own shade. As for proper hydration before you play, if you are not use to a dry heat, you need to start your hydration process at least a day before your tee time. Two days before is even better. Also watch your caffeine, and alcohol in take, prior to, and during your golf round. Also if you are fair skinned, lacking a tan, dress appropriately to avoid a sun burn. I actually golf in long sleeve shirts during July, and August when I golf there. Sun screen helps, but I have yet to find a brand that will prevent a sunburn after 3-5 hours in the sun. I have lived in Vegas for almost 60 years, so I do have some knowledge on skin damaged caused by the sun. i have golfed with many a tourists who started the day with their "no sun" skin, and left the course a nice shade of lobster red.
All the courses you listed are nice courses. I have played them all more than few times. I would suggest you check out Primm's courses before playing. They sometimes have a watering problem. Also the wind tends to be a factor a lot of the time. LV National has homes all around it. Arroyo is a nice course, but I have not played there in several years. If you have transportation, a trip north on I-15 to Mesquite, NV would be a nice day trip. Check out the Casablanca course there.
I play Desert Rose most of the time. It's close to my home, and it's cheap.
Probably a 30 minute drive from the Strip Hotels. I shoot the same scores regardless of he cost of green fees I pay, so less expensive is a good thing.