Meh.
I'm looking at the espn Sox stats chart and it shows that Campbell's WAR for 67 games was -1.0, Casas's for 29 games was -0.9, Toro's for 77 games was -0.4, and Yoshida's for 41 games is -0.3.
Of the four you cited, Hamilton's WAR for 84 games is +1.0 and Ref's for 62 games is +1.2.
I completely agree the Sox hitting is suspect, but find it hard to blame that on the bottom of the order guys--and you left out Wong with his -0.6 WAR in 56 games.
The real problem is the absence of Anthony and Abreu (and maybe Mayer) combined with the slumps of Bregman and Rafaela. Yesterday Cora batted Lowe, a reject from the Nationals a month ago, 3d in the lineup. He was hitless. Like you, I'm not much of an Eaton fan, but he had 2 hits with an rbi and a run scored.
It is what it is. The real strength of this team is the pitching.