What will the rooting hormone powder and the kelp fertilizer do? I am noticing some more dry yellow patches. Actually broke my water probe trying to get it into the yellowing grass. and that grayish thatchy looking grass like in picture 2 is still around. have cut way back on watering but now Phoenix is going through 110 temperatures so I don't want to cut back too much.

It should encourage the grass to root. St. Aug only spreads above ground, so a quarter inch of quality compost on all the bad spots will make a big difference--It needs something to grow into. It's super tough stuff once established, but you need to encourage rooting right now. Making it spread above ground will create more roots faster & you can level it all back out later if needed

How was the soil prepared for the sod?

How would you characterize the soil? Is it hard all the time even when wet? Sandy? Does water soak in quickly or stand on top for awhile?

That looks like a fungal disease to me. Give the corn meal 3 weeks to show improvement.

You have to stop the frequent watering and start with deep watering, but if your soil will not absorb deep watering, then start with an application of shampoo to allow better penetration. Spray any clear shampoo (I like generic baby shampoo) at a rate of 3 ounces per 1,000 square feet. Follow that with 1/2 to 1 inch of water. If you get runoff or standing water before you get at least 1/2 inch, then stop and wait 15 minutes for the water to soak in. Then resume/repeat until you get the 1/2 inch. You can measure 1/2 inch by placing cat food or tuna cans around the yard. Time how long it takes to fill the cans half way. Or for a full inch, time how long it takes to fill the cans. 1 inch is what you should be watering every time you water. With temps in the 110s, that should be once every 5 days. I know this works because we've been promoting it for 10 years on this forum. Also a friend of mine in Gilbert, AZ is doing it with his St Augustine.

Ok, the corn meal (store bought, all I could find) has been down for almost 2 weeks. I know the birds ate some of it. We prepared the soil with tilling, pulling out all the old grass remnants and working in gypsum and mulch. Then leveled it and lightly watered it before installing sod.

Should we do the compost and rooting hormon like reeljake says first and then the shampoo or start with the shampoo first? The edges of the sod are quite dry and hard. I broke my soil moisture meter trying to insert it.

Do all of them, shampoo is a great first step

I believe Winco has 25 pound bags of corn meal.