1)
To whom is "Ve'yad'u Mitzrayim ki Ani Hashem" referring?
1.
Seforno: To the Egyptians who remained in Egypt - who would take a lesson from their colleagues who had died, and do Teshuvah. 1
1
Because "Hashem does not want the Resha'im to die" (Yechezkel, 18:32 [Seforno]).