Complete Redemption is impossible until they unite and become one nation (6 December 2016, 6 Kislev, 5777)
Isaiah 11:
12 He will set up a banner for the nations,
And will assemble [Hebrew: "ve-asaf"] the outcasts of Israel,
And gather together [Hebrew: "YiKabets"] the dispersed of Judah
From the four corners of the earth.
The Midrash says "will assemble" in Hebrew "Ha-Asfu" i.e. "unite, become one" with the Ten Tribes and "gather together" in Hebrew "HiKabtsu" i.e. "gather in" with Judah and Benjamin.
The Malbim says:
# I explained in my commentary on the above verse (Isaiah 11:12) that the Ten Tribes are not scattered but rather outcast [Hebrew: "nidach" meaning outcast or driven out] to where we know not and only need to be gathered in.
The Tribes of Judah and Benjamin [i.e. the present-day Jews] are scattered to the four corners of the earth. They are not outcast since their location is known.
They [the Ten Tribes and Judah] need to be united...
# It has become quite clear to me that everywhere in Scripture where the Ten Tribes are spoken of as juxtaposed to Judah that Judah is referred to as 'Israel' as opposed to the Ten Tribes who are called 'Jacob' #.
===============================
4. Joseph Defeats Edom
"... The seed of Esau is not to be defeated by any other than the offspring of Joseph, as it says, [Obadiah 1:18] "Then the house of Jacob will be a fire; And the house of Joseph a flame; But the house of Esau will be as stubble" (Talmud, Baba Batra 123b).
" By the hand of who is the Kingdom of Edom defeated? By the hand of the Anointed Savior for War who comes out of Joseph" (Breishit Rabah 92;2).
===============================
 5. Two halves of Manasseh; One Half included many from Simeon and Judah.
 Fishel Mael discusses Manasseh being divided into two different sections each with its own character. One section was west of the Jordan river; the other to its east.
The eastern section absorbed many from the Tribes of Simeon and Judah.
See:
Why the USA is Manasseh: A Summation
http://www.britam.org/USAManasseh.html