1)
Why does it add "v'Hayah Mishkani Aleihem"?
1.
Targum Yonasan: [I will put My Mishkan] among them. Radak ? usually it says that the Shechinah is b'Soch. Here it says "Aleihem", to show that fear of Him will always be in them, for His honor will dwell among them forever.
2.
Malbim: There will be both matters ? the Mikdash among Yisrael, and Shechinas Hashem on all of Yisrael. They will not need Kedushas ha'Mikdash; they themselves will be the staves, Aron, Kodesh and Mikdash. Hashem will dwell on them ba'Kodesh, and the Mikdash will be between the inheritances of the Shevatim, like it says below (Perek 48).
