Rashi: It is a banquet hall. Sifri Balak 131 implies like this.

Rashi citing Kesuvos 69b: It is a mourner's house. Radak - the same applies to "v'Sar Mirzach Seruchim" (Amos 6:7). Malbim - it is the mourner at the time that the Mes is buried; people come to seek the Shalom of the living.

Radak citing his father: It refers to raising the voice, whether for crying or Simchah. Also in Arabic it means so.

Rashi: It is to lament.

Radak: I explained this above (it is consoling a mourner. Also Malbim says so. Refer to 15:5:2:2, 15:5:3:2.)

Rashi: When their father Avraham did Tzedakah and Mishpat, I gave to his seed Chesed and mercy - "v'Shamar Hashem Elokecha Lecha [Es Bris v'Es ha'Chesed Asher Nishba la'Avosecha]", "v'Nasan Lecha Rachamim (Devarim 7:12, 13:18). They reversed it - "ha'Hofchim l'La'anah Mishpat u'Tzedakah la'Aretz Hinichu" (Amos 5:7). Also I retracted and gathered to Myself My Chesed and mercy. Asafti means I removed, like "Asaf Elokim Es Cherpasi" (Bereishis 30:23).

Radak: The Shalom, Chesed and mercy that I gave to this nation, I took it from them and gathered them to Me. Since I gathered My Shalom from them, you should not seek their Shalom, nor their Aveilus or their Simchah.

Malbim: Since I gathered my Shalom, Chesed and mercy, do not seek their Shalom, eulogize (Chesed with the dead) or console (which is amidst mercy).