We are not going to see a true #1 back this year, maybe even next, because their talents are to diversified. We know that Mack wants to be able to run the ball reliably, without mistakes and with an emphasis on blocking. But you know he'll take blocking over the other two, which is why we're seeing so much Obi-Wan. Now, Obi brings the added advantage of being a spectacular pass-catching back even though he's a C+ runner. Obi's gonna be featured in at least 33% of plays this year where we have a single back.
Vondrell is the Mario of running backs. Much like the video game namesake, Mario was kinda good at a lot of stuff, but he wasn't super fast (Luigi), super strong (mushroom) and he can't fly (Queen). He's pretty decent at everything, but not spectacular. He'll be the solid true RB starter until he's unseated by either Foz or Cody.
Fozzy needs to get healthy. If he does, there's little question in my mind that Obi-Wan will become only a 3rd down back and Fozz will be the starter. He has a burst that makes me thick in the pants.
Cody's value remains to be seen. I love the guy and he's a real hammer, but he hasn't played early in games against a fresh D. If he shows the same 4-7 yard gains against Big XII competition, hell, put him in there until he gets tired! He has good speed too, so who knows what his upside is.