Why was Jesus called Jesus, and not Immanuel? Was the choice of Jesus (Joshua) in addition to Immanuel(Matthew 1: 21 and 23) in order to fulfil the prophecy in Deuteronomy 18: 15? This gives a message that Jesus, like His namesake, would lead Israel into the promised land and not Moses (the law).

Can the answers concentrate on the prophesy in Deuteronomy.
Because Emmanuel/Immanuel is a nick name.
It is like saying Clark Kent, his name is SuperMan, though people also know him as Man of Steel.
Which is the same with Jesus, he's name is Jesus of Nazareth, we call him Jesus Christ (Christ means Messiah) but we know him as Emmanuel because he's God in the flesh who walked with us.

and the prophecy is 


  Isaiah 7:14 14 Therefore the Lord himself will give you a sign.
  Behold, the virgin shall conceive and bear a son, and shall call his
  name Immanuel.


(And Abram to Abraham has no connection to this. Abram did wrong things, lying to those kings and allowing Sarai to be taken as the King's wife while Abram accepted the good/provision over Sarai. A man to be Father of all nations should not bare a name and remembrance of someone who lied and gave up his wife. God had to change his name to Abraham.
The thing was back in those times, names actually meant something. Jacob's name meant cheating and his name was changed to Israel. Jacob who would become the first to bear Israel was cheating a lot of people and did wrong things, so we cannot let the Jews bare the forever name Jacob to someone who cheats. That was why God had to change his name to Israel. Saul people knew him as a persecutor so he had to change his name to Paul.
I do think it's important for us to look at our name meanings for they can impact our lives. If name makes changes to our life as a bad thing, it is best to change our name. If you look at the prophet names in the bible, they all have good meaning outcome like David means beloved.)

God bless