The reason Esau brought so many soldiers was not only to intimidate Jacob. If Jacob was killed, Esau would lay the blame on one of the soldiers.

This behavior came from Esau's respect for his father and hatred towards Jacob. Esau did not want his father to think that he killed Jacob.

At the time Esau met Jacob, Benjamin was not born yet. Benyamin was one of the few people in the world who never sinned. Had Benyamin been with Jacob's group, who bowed down to Esau, he would not have been considered to have never sinned.