I don't really agree that Cristiano is not a typical Guardiola player. The young CR7 definitely would have been with his dribbling prowess and technique. He's not that player anymore but still has world class runs and world class finishing on top of a tidy technique, good strength and decent pace. It's not as if Guardiola only played Messis, Xavis and Iniestas. He was also very successful with Pedro, Lewandowski or Müller. Runs and spatial awareness are very important to him and Ronaldo delivers both at a world class level. And even if Ronaldo pales at most attacking disciplines compared to Messi, his link up play, ball control is still elite for a center forward (or at least was not too long ago). I know he's often described as some sort of Inzaghi these days but that's a consequence of being compared to Messi all the time, IMO. Very few can come off looking good in that comparison, let alone at 36.
Moreover, Guardiola has opened up to other tactical approaches at City. They cross and take shots from a difference quite a lot compared to Pep's Barca, especially de Bruyne. And with Sterling fallen out of favor, they definitely could use somebody to make great runs. Most of their players like to have the ball at their feet.