What is the meaning of "v'Lo Yihyeh l'Egypt Ma'ase..."?
Radak, Malbim: No deed will remain for Egypt to do, that will help it.
Radak citing Targum Yonasan 1 : Egypt will not have any counsel [to save it].
Our text of Yonason does not say so. (PF)
What is the significance of "Rosh v'Zanav Kipah v'Agmon"?
Rashi: These are the witches and astrologers 1 . In the sky there are constellations and stars with these names; they are in the form of a head and tail. They are in Mazal Teleh (lamb).
Rashi citing Targum Yonasan: [Egypt will not have a king, who is at the] head, governor, ruler or Itron 2 .
Radak: Rosh v'Zanav is a metaphor for the great Chachamim of Egypt, and the smaller Chachamim. Kipah are strong in Chachmah, and Agmon are weak. The matter is repeated in different words. All its Chachamim and witches will strive to save Egypt from its evil [punishment], but it will not help.
Malbim: Rosh v'Zanav are the great and small leaders. Kipah is a Gibor or Ashir; Agmon is a weak commoner. All of them will slacken from doing anything.