1)
Why did they say "Gam Esmol Gam Shilshom"?
1.
Malbim: Do not say that Yehudah made you king first - also before, you led us! 1
1
How could they say so? They accepted Sha'ul as their king, and did not protest when he sought to kill David! (PF)
2)
Why is there a Hei at the end of "Hayisah"?
1.
Radak: It is read with the next word "Motzi", as if it is written ha'Motzi. The same applies to "Yadatah Shachar Mekomo" (Iyov 38:12).
3)
Why is there no Aleph at the end of "ha'Mevi"?
1.
Radak: We find like this - "ha'Yoresh Avi Lach" (Michah 1:15).