1.

Radak citing Targum Yonasan: They are Talmidim of the Nevi'im.

1.

Radak: This is like b'Veis Kel.

1.

Radak (1): Hashem told Eliyahu; he did not reveal it to Elisha. Also Elisha knew via Nevu'ah - "Gam Ani Yadati Hecheshu" (verse 3). It was told to the other Nevi'im, and all the more so to [Elisha]!

2.

Malbim: Mekubalim say that an Ish ha'Elokim amidst his Talmidim is like the heart that gives life to the body. Limbs closer to the heart receive more life and influence. When he departs, the limbs further away sense the departure before the close limbs. Therefore, Bnei ha'Nevi'im sensed first that their heart and Nefesh will leave.

1.

Rashi (from Tosefta Sotah 12:5): This teaches that they were equal to Eliyahu ¹ .

1.

Malbim #1: An Ish ha'Elokim amidst his Talmidim is like their heart (refer to 2:3:1:2). If also Elisha, who is close to him, feels that he will be taken, this is a Siman that it will happen very soon.

2 Malbim #2: (a) Sometimes a man of Ru'ach dies due to sins of the generation; they are not worthy that this Divine light shine on them. Hashem wants to darken for them, and make his light set, and not illuminate. Then, [his death] is hidden from Bnei ha'Nevi'im and those who receive from him, lest they prepare to receive his light when he dies. He is taken suddenly, so their feet will be stricken on dark mountains. (b) Sometimes he dies due to his perfection. He reached his time to die and ascend to his place [in the world to come], and his Talmidim should inherit his crown. Then he tells his Talmid, so he will rest his hands on him. This was the Safek of Bnei ha'Nevi'im. If it is for the first reason, they must pray that Hashem retract from His anger at them (and allow them to get from Eliyahu's light).

1.

Radak citing Targum Yonasan: This is a command (be quiet). It is as if there is a Patach under the Hei.

2.

Radak citing his father: They were quiet.

3.

Malbim: You need not pray. Eliyahu will not be taken due to sins of the generation, rather, because he reached his perfection (refer to 2:3:3:2).