1)
Why did others tell Mordechai, and not Hasach himself?
1.
Torah Temimah citing Megilah 15a: This teaches that one should not report back when his mission fails (she refused to go to the king).
2.
Targum: Haman saw that Hasach (Daniel) is going to Esther. He got angry at him, and killed him. Micha'el and Gavriel told her words to Mordechai.
3.
Malbim: Refer to 4:10:1:1.
