On deserves, Arenado's back ups should be Jeimer and Davis, however there's going to be a push for Riley.
As nice as Thomas's season has been, I think there's a lot of outfielders who are hitting better or similar. Can't really argue about Acuna / Carroll / Betts. Soto as well, and probably Tatis. Thomas is more in the mix with Nimmo (remember, a Met has to go), Yelich, Reynolds, and perhaps Castellanos and Happ.
My guess it's one or the other - Lane or Candy. I give Candy an edge. It's too easy to fill in with other teams that need representation when there's an indisputable case for Candy.