Based on true seeds, KU has the easiest path to the Final Four. Louisville is the weakest 2 seed (8th overall), Purdue is the weakest 4 seed (16th overall), Iowa St. is the weakest 5 seed (20th overall), Creighton is the weakest 6 seed (24th overall), Michigan is the 2nd weakest 7 seed (27th overall), and Michigan St. is the 2nd weakest 9 seed (37th overall).
Oregon is the strongest 3 seed (9th overall), but the reality is they’re probably the weakest 3 seed with Chris Boucher’s injury factored in. Miami is the 2nd strongest 8 seed (30th overall), but they’re one of the most offensively challenged teams in the field.
So according to the NCAA Selection Committee, we have the weakest 2, 4, 5, and 6 seeds and the 2nd weakest 7 and 9 seeds.
Here’s the Wikipedia for the true seeds https://en.wikipedia.org/wiki/2017_NCAA_Division_I_Men’s_Basketball_Tournament#Tournament_seeds