All I know is Blonsky is outclassed by the other two at full power. Tagging Hulk with guns isn't really that impressive. Evasion isn't better than Bucky's, and Bucky can also block bullets. CQC feats are lacking, while WS and KM have a good amount of skill showings against other fighters on their skill level and size. Blonsky may not get one-shotted, but I seriously doubt he's coming up on top here.
Killmonger has standard armor that can protect from small arms fire as seen in his fight with Klaue. Bucky's arm is bulletproof. However, without vibranium, I think Killmonger's at a disadvantage against Bucky. T'Challa did put up a fight against Bucky h2h, and while KM is basically BP's equal, Bucky gets all his gear here, and his arm seems much more durable than Killmonger's armor. Killmonger did kill Klaue, but Klaue had only one arm. I doubt in a firefight that Bucky would go down from anything Killmonger has minus explosives in a direct fight. But what really seals it for me that Bucky has the advantage is how he moved out of the way and vanished from the RPG when Black Widow tried to shoot him. Killmonger tanked Klaue's bullet and shot him back, but without vibranium, he's probably getting blown up or pierced by Bucky's rifle.