I think they can be okay. Certainly two things that will need attention is the SS 2nd double plays and how fluid and mistake-free they can be and of course Dever's throws.
Both things could be improved and should be. I don't see Hanley as a dire liability even though I'd like him and his contract gone.
You are right, none of them are plus defenders, but none of them should remain really bad either.
We will probably see!