Love it. You have no peer in laying out solutions--or just data, for that matter.
And I actually agree on the infield with Devers, Story, Reyes/Urias, and Casas, especially if Reyes can keep hitting. But the real point of agreement is that to me Devers and Casas are good enough on defense and have the good bats. As for Story, he's got the glove, but it should would be nice to the freaking bat. But my sniveling counterpoint is that the Sox already have this fix right now--except Reyes is on the IL--so this really isn't a fix.
As for the outfield, I would keep Dugo, but would have absolutely no objection to moving Duvall over to RF--a good righty bat is pretty important at Fenway. But, when you do that, you put an unproven player, Rafaela, in CF.
As for Yoshida as full-time DH, don't forget that having Turner DH now and then was good for Turner. And next year the same could apply to other players.
Finally, let's not forget that Manny Ramirez was our leftfielder on two WS teams, 2004 and 2007. Handing LF over to Ref and Duran--in order, as you say, to fix the defense--seems to me to be bass ackwards. LF at Fenway has always been reserved for great bats, not great gloves.