What is the meaning of "Charadt Eleinu Es Kol ha'Charadah ha'Zos"?
Rashi: You put this matter to your heart (to build this room) for our sake 1 . This is like "v'Chared El Devari" (Yeshayah 66:2) - to be careful about the matter, that it be done, and put it to heart.
Radak: Charadah is movement and efforts for a matter. The same applies to "va'Yecherdu Ziknei ha'Ir Likraso" (Shmuel I, 16:4) and "Yecherdu ch'Tzipor mi'Mitzrayim" (Hoshe'a 11:11). Yonason translates like this.
Malbim: This is like a good guest, who says 'all the Ba'al ha'Bayis' toil, he toiled for me' (Brachos 58a).
Why did he say "Mah La'asos Lach"?
Rashi: Presumably, you need something, and therefore did all this for is (so we will do for you in return).
Me'iri (Brachos 10b): Since he benefited from her, he needed to return benefit. (Refer to 4:8:5:1*.) Malbim - I can benefit you naturally, via speaking to leaders of the country. (He was esteemed in their eyes; they would do all that he requests.) Or, I can get Hashem to help you, via Tefilah, a miracle or uprooting nature.
What is "Ledaber Lach El ha'Melech Oh El Sar ha'Tzava"?
Radak: It is to speak to them on behalf of you, if you need. 1
Alshich (based on Kabalah): It is to speak on behalf of you to the King of the world, or the head general above to advocate for you. (It was Rosh Hashanah.)
What is "b'Soch Ami Anochi Yosheves"?
Rashi: I am amidst my relatives. No one harms me. I do not need the king or the head general!
Radak: I am amidst my nation and family. They will speak for me if I need!
Radak (14) citing Targum Yonasan: B'Go Iskei Ami Ana Mesovara. Yefe To'ar (on Bereishis Rabah 58:17) - i.e. I am serene and confident amidst affairs of my nation. Yayin ha'Tov - in matters of my nation (taxes) I am exempted.
Alshich: (It was Rosh Hashanah.) I am amidst my nation; in their merit, it will be good also for me. If you mention (intercede for) me alone, they will investigate my ledger (merits and Aveiros) 1 .
Surely everyone is judged on Rosh Hashanah for his own deeds! Perhaps interceding for her would diminish her share in the nation's merit, and she would be judged more strictly according to her deeds. (PF)
