To whom does Hashem "Hibadlu" refer?
Ramban #1 (citing R. Chananel): It refer to the whole of Yisrael. 1
To whom is "ha'Eidah ha'Zos referring?
Ramban #1 (citing R. Chananel): It refers to Korach and his congregation.
Ramban #2: It refers to all of Yisrael, 1 who were dithering between Korach and Moshe, and were therefore Chayav Misah bi'Yedei Shamayim.
Ramban: For doubting their Rebbi's veracity (See Sanhedrin, 110a) and for negating the prophecy of a Navi.
If "ha'Eidah ha'Zos refer to all of Yisrael, why did Hashem not add 've'E'eseh eschem le'Goy Gadol'?
Why did Hashem instruct Moshe and Aharon to leave the vicinity of the congregation of Korach?