Didn't Coutinho always play wide left for them,i can't recall him playing midfield for them much.
I think the reason they bought Keita was being impressed with his dribbling stats playing in a high pressing team,who could fix their limitations against park the bus teams.
Fabinho is a pure destroyer with highest stats in France at winning headers interceptions and tackling,he is mobile and quick as he used to be an attacking RB until 2 seasons ago,they have a quicker DM now who can get around the pitch better than the likes of Henderson and Can.
And now they have upgraded by far on a GK who's supposedly just as good as Edison with his feet.
Their recruitment just seems clever,they don't seem to buy players and shoehorn them in another position,they seem to be patient waiting for the right player for the right role.
Moratti and Paratici who are in charge of recruitment at Juventus is who their recruitment style/mantra reminds me of.