1)
What is the "Yad" to which the Pasuk is referring?
1.
Rashi (citing Targum Onkelos), Targum Yonasan and Sifri: It is a prepared location 1 (not literally a hand). 2
2.
Rosh: It refers to the merit of Avraham Avinu, which stands-up for Yisrael in exile. Even though Z'chus Avos terminated, that is with regard to being answered immediately in their merits, like Eliyahu on Har ha'Carmel, but their merit will never cease from their seed.
2)
Which camp is "mi'Chutz la'Machaneh" referring to?