Was the Scapegoat of Leviticus an allusion to Barabbas? There are several similarities between the selection of the Scapegoat, and the selection of Jesus as our sacrifice.

Leviticus 16:7  KJV  And he shall take the two goats, and present them before the LORD at the door of the tabernacle of the congregation.
Matthew 27:17   KJV  Therefore when they were gathered together, Pilate said unto them, Whom will ye that I release unto you? Barabbas, or Jesus which is called Christ?
Leviticus 16:8  And Aaron shall cast lots upon the two goats; one lot for the LORD, and the other lot for the scapegoat.
Matthew 27:21  KJV   The governor answered and said unto them, Whether of the twain will ye that I release unto you? They said, Barabbas.
Leviticus 16:9  And Aaron shall bring the goat upon which the LORD'S lot fell, and offer him for a sin offering.
Leviticus 16:10  But the goat, on which the lot fell to be the scapegoat, shall be presented alive before the LORD, to make an atonement with him, and to let him go for a scapegoat into the wilderness.
Matthew 27:26  KJV  Then released he Barabbas unto them: and when he had scourged Jesus, he delivered him to be crucified.

Do these passage suggestion a connection betwen the Scapegoat of Leviticus and the figure of Barabbas in the passion narrative?
I suspect not.

For two reasons:


The "goat upon which the Lord's lot fell" was still used as an offering. Barabbas was simply released.
It makes more sense that Jesus is the type both of the sin offering and the scapegoat -- especially given how repetitively the sacrificial system prefigured the Messiah in many other aspects. This repeating imagery amounts at last to layers of nuanced meaning which resolve into a fuller picture of the Messiah than any one (or select few) of the metaphors could have provided.