Ok - so thinking about this logically - 2nd Test line up was Cook, Hameed, Root, Duckett, Ali, Stokes, Bairstow, Rashid, Ansari, Broad, Anderson.
Let's assume that Cook, Hameed, Root, Ali, Stokes, Bairstow, Rashid and Anderson are in for the 3rd Test.
That leaves 3 unknowns which we should take one at a time to address!
1. Broad - would be playing but has issues with his foot. Obvious replacement if he is fit again is likely to be Woakes.
2. Duckett - The shot he played in the last innings does seem to suggest that he has mental issues. He would have normally put a bad ball like that away 99% of the time in his sleep! So if the Management think he is ok to bat still, then leave him in as the wicket will (supposedly) play better for batsmen in the next Test? But if they are worried about Duckett's mental state then they may pull him - replacement? Probably Buttler (maybe at 4, maybe slightly lower down the order)
3. Ansari - decent player who hasn't come alive in any match yet. Unlikely to play in the 3rd Test if the wicket is not expected to require 3 spinners! So if they decide that Rashid and Ali are enough, with the option of Root taking a few overs if required, then Ansari will be the one rested! Therefore replacement is likely to be pace bowler - hopefully Ball (please not Finn until he shows genuine improvement again) as Ball has shown his quality already in Bangladesh!
I can see Broad and Ansari definitely being rested! No opinion on Duckett as I have no clue as to his frame of mind currently but would hope that the Management know whether he is mentally fit enough or not. So I think either:
Cook, Hameed, Root
Duckett, Ali, Stokes, Bairstow,
Woakes, Rashid, Ball, Anderson.
Or if Duckett is left out:
Cook, Hameed, Root,
Bairstow, Ali, Stokes, Buttler,
Woakes, Rashid, Ball, Anderson
Bairstow could bat 4 as there is always the option of Buttler taking the gloves if Bairstow goes big with the bat!!