Shaw has shown life with his bat in July, so unless Suarez' price is a bargain, I'd target a proven utility infielder to upgrade from Berti/Brujan and platoon with Shaw.
I'd prioritize spending the Cubs elite prospect capital on proven relief pitchers. If a solid starter could be had at a decent price great. A starting rotation of: Imanaga, Boyd, Taillon & (Horton or Rea) should be serviceable in the playoffs. So focus on quality relievers who have the ability to pitch most games of a playoff series.