Norma,
I was most interested in Mike's comments on the importance of the type of cheese for the Detroit style pizza. I have to believe that with all of the testing and experimenting he did with cheeses that his comments have some validity. So, with that in mind, I revisited what I believe we know about the types of cheeses used by the various purveyors of the Detroit style pizza.
Starting with Klausie's, I think it is fair to say that they use brick cheese to the extent it is available to them. Buddy's uses brick cheese. Shield's is reported to use brick cheese. Loui's uses two cheeses on its pizzas, but mozzarella cheese is not one of them. Other than that, we do not know what the two cheeses are although I am guessing that brick cheese may be one of them since Louis Tourtois worked for years at Buddy's and Shield's, and brick cheese is readily available to him (and now his son). The Detroit Pizza Style Co uses mozzarella cheese and brick cheese but it is not clear whether the two cheeses are blended. It could be that the brick cheese is placed around the sides of the pans, to become nicely caramelized during baking, and the mozzarella cheese is used for the rest of the pizza. However, I have read that the cheeses are shredded. Brown Dog Pizza in Telluride, CO uses whole milk mozzarella cheese (I believe it is Grande) and aged white cheddar cheese but, again, we don't know if the cheeses are blended or added separately. Jet's uses Grande low-moisture part-skim mozzarella cheese although it should be noted that Jet's does not call their square pizza "Detroit style". That may be intentional since they are expanding nationwide and do not wish to be viewed as strictly a Detroit style pizza operator. We do not know what cheese or cheese blend Via 313 uses.
With the above as background, I think it is safe to say that brick cheese is a good choice if one wants to get good caramelization of the cheese. Looking at pizzas made using only mozzarella cheese, such as the Jet's pizza shown at Reply 70 at
http://www.pizzamaking.com/forum/index.php/topic,8247.msg135948.html#msg135948, I see that the sides are browned but I don't see that vertical dam of caramelized cheese that seems to characterize the basic Detroit style pizzas made by Buddy's, Shield's, Loui's, and Cloverleaf/Detroit Pizza Style Co, at least as exemplified by the photos shown at
http://www.lthforum.com/bb/viewtopic.php?f=15&t=35487. Likewise for the Klausie's Detroit style pizza. Several of the Brown Dog Detroit style pizzas I have seen also exhibit that vertical dam of caramelized cheese, so maybe the white cheddar cheese contributes to that effect. Looking at the Via 313 photos at
http://www.yelp.com/biz_photos/via-313-pizza-austin?select=quBst2A8N8Sx8gMCl7E7Jg#571KK5bmUn7n9fZZAva86g, some but not all of their pizzas exhibit that effect to one degree or another. I am guessing that one of their cheeses may be brick cheese or maybe a white cheddar cheese. Or maybe I am simply reading too much into all of this and that any cheese if forced along the sides of the pan will caramelize in a dam-like way.
Mike cuts the cheese into cubes and tops the panbaked crust with them
I believe the author of the article meant to say "diced". It would seem impractical to cut the brick cheese into cubes, presumably by hand. As noted in the photo at
http://cache.daylife.com/imageserve/08Mf788bNv6xv/340x.jpg, Buddy's, which was the inspiration of Mike at Klausie's, looks to use a diced cheese.
In the second article you referenced it said that butter is used to brush the crusts. I wonder why that is needed, unless it is needed to moisten up the par-baked crust.
I first saw reference to the use of butter and also a twice bake in a comment by a poster at
http://www.urbanspoon.com/r/25/1587230/restaurant/Inside-the-Beltline/Klausies-Pizza-food-truck-Raleigh. I thought that perhaps the commenter was just paraphrasing what wikipedia says about the Detroit style pizza at
http://en.wikipedia.org/wiki/Detroit-style_pizza, to wit,
The crust of a Detroit-style pizza is noteworthy because in addition to occasionally being twice-baked, it is usually baked in a well-oiled pan to a chewy medium-well-done state that gives the bottom and edges of the crust a fried/crunchy texture. Some parlors will apply melted butter with a soft brush prior to baking. In Klausie's case, it looks like both statements apply but with the butter added after baking rather than before. Like you, I suspect the butter helps soften the crust somewhat but also to give more flavor to the crust (the often sought after "buttery" crust).
Peter