When I made the last deep-dish pizza, a "lite" version of DKM's recipe (see http://www.pizzamaking.com/yabbse/index.php?board=5;action=display;threadid=638;start=0
), I strained the 6-in-1 tomatoes in a sieve to make the tomatoes thicker. This seemed to help reduce the sliding of the contents once the pizza was cut. I got the idea after reading that Steve had combined 6-in-1 tomatoes with the considerably thicker Bonta tomatoes to achieve a similar result. If you precook and drain ingredients such as sausage and pepperoni, this will help reduce the fat in the pizza and result in less sliding also. (I did this with the "lite" version).
As for the difficulty in combining the oil after kneading the dough, this is quite common when you are working with small amounts of dough and I, too, have sometimes found it necessary to stop the mixer and work on the dough by hand to help incorporate the oil. In the "lite" version I made recently, I used a food processor because it does a better job with small amounts of dough. FYI, the late addition of the oil is to allow more complete hydration of the flour by the water. The theory is that adding the oil to the bowl along with the water interferes with the hydration. Adding the oil separately is the approach recommended by Tom Lehmann, the dough expert at PMQ, and is widely followed (I do this for all pizza doughs). If you chose to go to a shortening for your next effort, it can be mixed in with the flour. This should help with the kneading step.
The yellow coloration you experienced is most likely due to the particular brand of cornmeal you used. Although the deep dish pizzas I have made using cornmeal didn't produce much coloration, I have seen brands in the supermarket that looked yellower than mine. In the "lite" version of the pizza I made, I intentionally added yellow coloring to try to get the Gino's look that I remembered from the days when I lived in the Chicago area.
Looking at your pizza is making me hungry. With the crust thickness adjustment you plan for the second pizza, I think you are headed in the right direction.