1)
What does "Imo" refer to?
1.
Rashi: Verse 7 said that Yehoshua will apportion land to nine Shevatim and [the second] half of Menasheh. [Moshe apportioned to] the first half of Menasheh, and Reuven and Gad. Radak - it is as if the verse mentioned the half to which Moshe gave. I.e. it is as if "va'Chetzi Shevet ha'Menasheh" was written twice. (Aderes Eliyahu)
2)
Why does the verse repeat "Asher Nasan? Ka'asher Nasan"?
1.
Malbim: They received like Moshe gave; Yehoshua did not change this.
