Esther 8:12, Question 2. Why do the letters stress that this would occur in all of the provinces?

The Malbim points out that in the wording of Haman’s letter, Haman had left out the detail that the attack would occur in every state so that the governors would not know yet that he planned to have a mass genocide. Haman did not want them to know that other governors received the same orders. Thinking their orders were unique, the governors would focus on the work at hand, and not be unnecessarily concerned and overwhelmed regarding the success of the operation.

Esther 8:11, Question 5. Why do the letters call the threat against the Jewish lives “al nafsham” (“on their souls”)?

In Machir Yayin, the Rema writes that the verse’s use of the phrase “al nafsham” (“on their souls”) rather than “al gufam” (“on their bodies”) implies that the Jews’ targets were their spiritual enemies, not their physical enemies. In other words, Jewish survival depends upon their defending themselves from sin.
The Sfas Emes focuses on the word al (“on”). He explains in this context that teshuva out of a sense of love is greater than teshuva out of fear. According to him, the Jews were on a higher level at this point – no longer threatened with annihilation – and the verse therefore uses the word al.

יב בְּיוֹם אֶחָד בְּכָל–מְדִינוֹת הַמֶּלֶךְ אֲחַשְׁוֵרוֹשׁ בִּשְׁלוֹשָׁה עָשָׂר לְחֹדֶשׁ שְׁנֵים–עָשָׂר הוּא–חֹדֶשׁ אֲדָר

12. “On one day in all the states of King Achashverosh, on the thirteenth of the twelfth month, which is the month of Adar.”

Rashi explains that the gentiles’ property was only included in the letter because the Jews’ property had been threatened in Haman’s original decree.
The Vilna Gaon writes that the Jews did not want to plunder, and it would have been enough for them to be out of this great danger, but Mordechai and Esther had to have parallel language to Haman’s decree (Esther 3:13).
The Maamar Mordechai points out that when a government kills someone, it seizes that person’s property; here, Achashverosh wanted to give it to the Jews.
Malbim notes that there was less time for looting to stress that the Jews were really focused on self-defense.
In Yosef Lekach’s opinion, Achashverosh gave permission to take spoils, but Mordechai limited the time in which it could be done to lessen the Jews’ ability to enjoy the plunder in order to avoid the same problem as occurred in the time of Shaul (Shmuel 1 15:9), when they did not completely wipe out the property of Amalek for the sake of their flocks.
R’ Moshe Dovid Valle notes that the Torah (Devarim 19:18) speaks of eidim zomemim, who are false witnesses proven to have not been in the location of the crime regarding which they are testifying. Their punishment is to receive the same consequences their testimony would have incurred on the person about whom they testified. Here, too, the enemies of the Jews – having testified falsely about the Jews – receive the consequences they wanted for us.