Ruben Neves
He has an expansive passing range, which allows him to ping passes to the flanks with consummate ease. Very much like Alonso in that respect. However, and perhaps inconsequential at this moment of time, he doesn't yet consistently make those incisive probing passes between the lines. Additionally, he's fairly mobile and skilful which allows him to gracefully avoid players that come within close proximity, by performing an instinctive piece of trickery. At Real Madrid, particularly under the guidance under Jose, Alonso often played in a 4-2-3-1 with a defensive box to box midfielder alongside him, like Khedira, and Ozil as the no.10 ahead of him Similarly, we should be looking at a box to box midfielder with great defensive capabilities to compensate for Neves' defensive frailties, as well as the fact that Pogba looked more liberated with a midfield that had more defensive solidarity, than he had in his 1st season at Juve. Neves is no stranger to having a meteoric rise as exemplified by the fact he bypassed both the U19s, and B team, and he's the youngest Portuguese player to grace the Champions League, which means we would be in good stead of having a player with a high ceiling.
Johannes Geis
Amazing technique. He can put a formidable amount of pressure on the ball with little back lift. He's great at corners, direct and indirect free kicks, crosses in open play, picking out players situated on either flank, irrespective of where he is on the pitch, and shooting from distance. He's very similar to Alonso. Unfortunately, Geis is overly keen to hit those cross field diagonal balls which can make his style tedious as the game wares on. He's also immobile, and disconcertingly reckless in the tackle.
Jorginho
Jorginho, a deep lying playmaker in a similar mould of Pirlo. He's in many ways suspect defensively, and relies on Allan who has a particularly noteworthy workrate, aggressive, dogged determination and I remember when he played for Udinese, his interceptions and tackle rates were consistently in the top 2 alongside Vidal. Similarly, Pirlo relied on Vidal, Marchisio and Pogba to do his dirty work, or Gattuso and Seedorf at Ac Milan. Jorginho, compensates for this with his ability to instigate attacks from the back with his commendable composure when on the ball. Last season, Jorginho made 180 passes in one game, to my knowledge, that's only bettered by Alonso in recent years. He was a crucial cog for Maurizio Sarri, as Napoli averaged 59.3% possession, the most in Serie A (before they averaged the 5th most possesion). Only Barca, Bayern, PSG and Dortmund averaged more in the top 5 European leagues.
Leandro Paredes
Most comparable to Sergio Busquets. Great at making those incisive probing passes through the lines. Moreover, he's very mobile, which is important as he's comfortable in manoeuvring himself out of tight spaces, although at times he undoes his aesthetically pleasing work by getting ahead of himself, and going for the spectacular. For instance, there would be times when he's escaped the pressing of a player, then escapes another in quick succession and instead of releasing the ball, he would then attempt a raking 40 yard pass which goes out of play. If he can stay slightly limit his flamboyant nature, whilst concurrently, being productive then he can become the quite the player. His biggest weakness is that he can be susceptible to holding onto the ball for too long, much like Busquets who often invites pressure, although at times it can be a positive, as sometimes he buys a foul when limited passing opportunities arise.
Julian Weigl
Given that Carrick is my favourite Man Utd player, Weigl is my ideal option as he's more comparable to Carrick than the aforementioned.
My top 3 in order of preference would go something like this:
1. Weigl
2. Leandro Paredes
3. Ruben Neves
Subject to change of course, given you can never predict which unknown quantity may arise.
You donkey !