What is the significance of Yaakov pitching his tent near this site, "Migdal Eder"?
Targum Yonasan: Because at the end of days, Mashi'ach will reveal himself from there. 1
Oznayim la'Torah: On his outward journey to Charan, following his dream, he said, "Mah Nora ha'Makom ha'Zeh" - and that, had he known, he would never have slept in such a holy place. Now that he was aware of the holiness of the place, he did not pitch his tent, not only in Beis El itself, but even in its vicinity. 2
See Rashi to Michah 4:8.
Oznayim la'Torah: See Shekalim 7:4, which connects Migdal Eder with the outskirts of Yerushalayim. In fact, it is close to Beis Lechem - See Rashbam.
Why does the Torah spell "Ohaloh" with a 'Hey' at the end?
Oznayim la'Torah: Because it refers to the tent of Bilhah. 1
Why does it say "va'Yisa Yisrael"?
Ha'amek Davar: To relieve his pain over Rachel's death, he went in the way of Yisrael - seclusion and clinging (to Hashem). One should bless on a death just like on good tidings - i.e. to accept the loss b'Simchah (Berachos 60b)!