Concerning the cornerbacks and practicing: this is something that I don't know about so more experienced board members can perhaps clear up. It seems to me that coaches like to practice ones vs ones, or ones vs twos. The receivers on the ones probably can't "go" full steam all practice long. Twos come in but they get the edge taken off too. This is where threes or walk-ons sometimes fill the gaps to allow practice to go full speed.
Now, lets say that you were a DB coach, and you'd decided that Jackson and Wood would likely be the ones. They get tested by the offensive ones or at worst the twos. But now who are your twos at corner? You have maybe six guys all vying for the role [or even ultimately higher] but you really haven't seen them in true action enough to separate them out. Are you going to just pick out a Brown or an Atkinson and run them all the time against your ones and twos, but by the time you get Shumate or Russell [for example] in there, they are running mainly against threes or walk-ons? How are you going to filter with that pattern?
It seems to me that I would have sat down with my D-Backs and told them straight: gentlemen, Bennett and Lo are going to get the reps with the ones until they give their spot away. After that we're going to mix it up so that all of you are going to have to defend TJ, Tyler when he's flanked, Chris, Davaris, --- and you'll have your chances to show what you can do. Don't pay any attention to "two" or "three" now. That will sort itself out.
As I say. I don't know whether the speculation is embedded in actual football practice pattern reality or not, so you guys can let me know where the concept falls down.