Is "ha'El Adonecha v'Elecha" said in astonishment?
Rashi (Yeshayah 36:12): Yes; there is Chataf Patach 1 under the Hei. I was not sent only to the two 2 of you, rather, to the entire nation, so they will fear, and Chizkiyah will not entice them to rebel!
Malbim (Yeshayah 36:12): Yes. (a) Since Chizkiyah gave a tax and rebelled, there is no solution for him; he must be punished. He will be deposed, and his nation will be exiled, like others who rebelled against Melech Ashur. The Shelichus is to the nation 3 , that they should not heed Chizkiyah; they should go out [to Melech Ashur] and submit that he do to them as he desires. (b) Melech Ashur is not weak, that he needs to persuade Chizkiyah verbally. He can force Chizkiyah via the sword! He had mercy on the nation. Rather than starve to death, they should rebel against Chizkiyah and come to Melech Ashur.
Why does it say "ha'Al Adonecha" and "ha'Al ha'Anashim"?
Radak: This is like ha'El Adonecha and ha'El ha'Anashim, and so it says in Yeshayah 36:12 "ha'El Adonecha 1 ."
However, also there it says "ha'Al ha'Anashim" (PF).
Chizkiyah's three men spoke to Ravshake. Why did he say "Adonecha v'Elecha" (singular)?
Radak: He addressed only Elyakim, the greatest of the three. Similarly, [for this reason] verse 26 says "va'Yomer Elyakim" (singular), even though all three of them said so.
Why is it written Choreihem, and we pronounce it Tzo'asam?
Rashi: Excrement comes out of the Chor (hole, i.e. anus). We pronounce it in a nicer expression (Megilah 25b).
Why did he say that they will eat their excrement?
Rashi: This will result from [awesome] hunger during the siege. Radak - you intend to be besieged until you will eat your excrement!
Why is it written Shineihem, and we pronounce it Meimei Ragleihem?
Rashi: Meimei Shineihem refers to soft excrement (diarrhea) that comes out of the anus, which has 'teeth'. Alternatively, excrement results from chewing with the teeth. We pronounce it in a nicer expression (Megilah 25b).
Radak: The Kesiv hints to hemorrhoids. Chazal (Shabbos 82a) said that if one cleans his anus with something flammable, his anal teeth fall out.
Kli Yakar: It refers to urine. Metzudas Tziyon - Shineihem is close to Shesen (urine).