1)
Why is this Nevu'ah put here?
1.
Malbim: Do not ask, Yisrael are in Galus now. They are not neighbors of Tzidon! I will gather them to their land ? Koresh will permit then to return to Eretz Yisrael.
2)
Why does it say "l'Avdi l'Yakov"?
1.
Rashi: Just like Yakov was given an inheritance without borders ? "u'Faratzta Yamah va'Kedmah v'Tzafonah va'Negbah" (Bereishis 28:14) [so Yisrael will receive].