I am also a Galatasaray fan, so i watched Onyekuru live throughout this season and can easily asses his strengths and weaknesses for Everton.
pro's:
-decent finishing ability despite being used on the wing.
-good technique and dribbling
-very good pace, infact this is the best thing about him.
con's:
-decisions: his final decision is really poor. he shoots when he needs to pass and pass when he rather needs to shoot.
(he is also VERY selfish which sometimes drives you mad, despite playing on the wing, he has 0 assists)
-consistency: this is maybe the biggest negative thing about him.. one week you'll think he is better then messi, then next week you'll even be surprised he made it to be a professional football player.
-strength:he is a tiny guy, dont expect him to hold the ball for you.
final note
7.5/10
Onyekuru is one of those guys that would dominate the Dutch league for example but anything higher, especially the EPL, i really am not sure if he is up for it.
his consistency and other mental weaknesses will be huge undermining factor for his development as a football player.
Despite his good stats, he really didnt impress Gala fans that much, Gala will probably will not seek to renew his loan deal, and that alone should tell you how ready he is for EPL challenge.