1)
What does "Bayis" refer to?
1.
Radak: It is the Heichal.
2)
What is the significance of "Asher Panav Derech ha'Kadim"?
1.
Malbim: I explained (Yeshayah 43:5) that Hashem's honor will be revealed via those exiled to the east, i.e. the 10 tribes ? "va'Yir'u mi'Ma'arav Es Shem Hashem umi'Mizrach Shemesh Es Kevodo" (ibid. 59:19). His honor will come from the east with them. Initially, His honor will not be revealed in the west, just they will hear His name.