City are set to sign Ake after reaching agreement over a £40 million deal following Bournemouth's relegation to the Championship.
But the impending arrival of the 25-year-old Dutchman has not put a stop to interest in Koulibaly and Torres, raising further question marks over the long-term plans for Nicolas Otamendi and John Stones.
Torres has also caught the eye of United but he wants assurances over playing time should he leave Villarreal this summer after playing regularly for the La Liga side last season.
The winger, 20, will move to the Etihad Stadium from Valencia for an initial €23m.
City could also pay another €10m to Valencia in bonus payments although sources have told ESPN that the conditions that would need to be met for the bonus to be paid are difficult to achieve.