Why does it say "Af Ki"?
Rashi: This is a Kal v'Chomer - all the more so. We find this in all of Tanach, e.g. "Anachnu Fo bi'Yhudah Yere'im v'Af Ki Nelech Ke'ilah" (Shmuel I, 23:3), "Hine bi'Hyoso Tamim Lo Ye'aseh li'Mlachah Af Ki Esh Achalaso" (below, 15:5).
What are "Shefatai"?
Rashi: My judgments.
Why are the four listed in a different order than in verses 13-20?
Malbim: He sent all four at once, in this order. Via the enemy's sword, there was hunger in the city, and evil Chayos ate those killed outside 1 , and there was Dever inside.
"V'Shikelatah" (15) implies that the Chayos killed people! (PF)
Did He send them to cut off people and animals?
Radak: It was proper to do so, but I had mercy, and I did not; I left a remnant.
QUESTIONS ON RASHI
Rashi writes that "Af Ki" is a Kal v'Chomer. What is the Kal v'Chomer?
Radak: When I send one of the four punishments on a land of Goyim, I eradicate it ? all the more so when I send all four, there should be eradication! I did not, like I promised "v'Osecha Lo E'eseh Chalah" (Yirmeyah 46:28).