Ronaldo and Messi are attackers, especially Ronaldo who is a poacher now basically. Messi can be sort of a playmaker/AM, but he is not in this team anyways. Sterling is vintage winger, he is groomed to become more of an attacker like they all are, but his strenghts are penetrating from wide positions, he absolutely sucks infront of goal majority of the time, except for the decisive moments that got him on this list.
I have no idea, maybe he did several saves, didnt watch PSG except 1 boring game vs Real. And Sirigu is benched by him for some while now, so much so that Sirigu will leave PSG in January, he said he will only go to a CL club. Even loose rumours he would come to us when Neto leaves. Which would be weird, changing bench for another.