Alright, this is how they stand. Currently in January, 3rd season.
Best players include Butland (still not as good as Cillessen in PES2015, that guy saved everything), Joe Gomez (an immovable object), Eric Dier (unbeatable in the air, great passing range) and Demarai Gray (stats are self-explanatory). But the three best players in the squad are, without a doubt, Will Hughes, Bamidele Alli and Zach Clough.
Starting with Alli. He's big, he's strong, quite good on the ball, but the best attributes are passing and shooting. He just has an animation that really resembles the real life Gilfy Sigurdsson (don't ask...), and his passes just feel so much more sticky than any other. Shooting is powerful and accurate from distance, low shots are a treat to the scoreline.
Clough resembles Messi. Short and explosive, feels almost like Bernardo Silva with his short dribbling and quick direction changes. Holds up play beautifully, and while only being 172 cm tall, if he gets enough space for a header it will go in. Excellent striker.
Hughes is by far the most influential player I've ever used, in any PES game. Even more than Bernardo Silva, André Silva or Goretzka back in PES2015. Since I've shifted to a 3-2-3-2 formation, with him as AMF, he scores almost more than my strikers, while keeping an amazing assist record. Strikers run by the sidelines up to the edge of the box, and Hughes darts through the centre. Passing is sublime, Weighted Pass is a great addition, dribbling is typical left footed magician, speed is more than expected. It just feels like a 85+ rated player.
Gomez, Chilwell, Dier, Alli and Gray have already flourish. Butland has had all that development (+10 OVR or so) in just 2.5 seasons.