Its swings and roundabouts with these lads, I think with every passing game you watch them its very difficult to say who is the best of the 3.
I would personally say Sancho has been the standout performer in the youth cup games this season. Foden best player v Reading in the earlier rounds and Stoke the other night, but Sancho was mesmerising against Southampton, Liverpool and Aston Villa in the previous rounds before the semis. Diaz has generally looked dangerous also in most of the rounds even when played up top as a false number 9.
I can agree that Foden and Brahim have similar qualities, but I would say one likes to be more similar to messi, the other more similar to Silva. I do think that Diaz tries to take more chances on the ball which is why he loses it more but at that age, players should not be discouraged from playing with freedom and expressing themselves.
They all need a chance at some point in the future though, top talent like this can not go to waste. I would also slot Matt Smith into this bracket who has been superb for under 18s this season and for the under 23s when called upon. Unlike Sancho and Diaz, Foden hasn't played a game for the under 23s so it will be interesting to see how he gets on.