Well actually, other than Higuain, another 3 key players to our game against barca are
1) Cuardrado, he can really wreck barca's defense on the wing with his trickery and crossing, and attracting fouls while bringing the ball from deep.
2) Mandzukic, his strength and aerial power is going to be a problem for mascherano etc.
3) Pjaca, a very rare breed of player who has height AND pace, two things that barca defense always have problem with
as for Dybala, I don't think he will be very effective against barca as I think Barca will force him to drop into midfield, and he doesnt seem like the kinda player that can dribble from deep like cuardardo. Hope he proves me wrong.