1)
Why does it say "Kachem"?
1.
Malbim: You must stay until they have rest and [divide their] inheritance, like you.
2)
Why does it say "Asher Nasan"?
1.
Malbim: Moshe gave it to you on this condition.
3)
What is "Mizrach Shemesh"?
1.
Rashi: It is the east side of the Yarden.