Kansas will struggle, but they are going to be far too talented to finish that low, IMO. I can't see them finishing any worse than 7th and that's an absolutely worst case. Again, my opinion.
Nebraska does return a somewhat talented defense, but Maric was nearly their entire offense last year. I just don't see where the points are going to come from to finish in the Top 3. I know the Big 12 North will be down a bit with no real dominant team, but I just don't see how they could finish above 5th.
That being said, anything could happen and there is no doubt that crazier things have happened.