Why did Moshe add the (otherwise superfuous) word "Banav ha'Nosarim"?
Rashi #1: To teach us that Elazar and Isamar survived the decree to die due to Aharon's participation in the sin of the Golden Calf. 1
Rashi #2 (in Chagigash, 11b), and Targum Yonasan 2 : Because Elazaar and Isamar were standing beside Nadav and Avihu when they brought the Ketores and it was only due to a miracle that they were saved from the fire (due to the merit of their father Aharon
Rashi: As the Torah indicates in Eikev Devarim, 9:20 - "where the word "Le'hashmido" refers to the death of all of Aharon's sons. And it was only due to Moshe's Tefilah that Elazar and Isamar were spared (as Moshe himself explained).
See Torah Temimah citing Yoma, 87b and note 29.
Seeing as Moshe had already spoken to Aharon's sons in Pasuk 6, why does the Torah write "Banav ha'Nosarin" only now?
Oznayim la'Torah: Because in Pasuk 6, he instructed them not to let their hair grow long or to rent their Begadim, and it is only after they accepted it in Pasuk 7, that they truly became Nosarim.
Which Minchah is "ha'Minchah" referring to?
Rashi: It is referring to both Minchas Shemini and the Minchah of Nachshon. 1
Ramban (on 9:17): The Minchas Nedavah of the people (besides the Minchas Nesachim of the Korban Tamid). 2
See Naso Bamidbar, 7:12 & 13. It is not referring to the Minchah of Rosh Chodesh, since it was not brought on account of the Milu'im (See Sifsei Chachamim).
Oznayim la'Torah: Which had been taken to the south-western corner of the Mizbe'ach and was left there after the Kemitzah
Why did Moshe find it necessary to instruct them to eat the Minchah?
Rashi (on Pasuk 19): Because, although a Kohen Gadol who is an Onen is permitted to bring Korbanos, he is not permitted to eat them.
Seeing as all S'tam Menachos are brought as Matzos, why did Moshe need to add the word " ve
Rashi: Because this Minchah was unique, inasmuch as it was a one-time Minchas Tzibur.
Does this mean that they had to eat the Matzos standing beside the Mizbe'ach?
Sifra: In fact, they were permitted to eat it anywhere in the Azarah 1
Why does the Torah add "Ki Kodesh Kodshim Hi"?
QUESTIONS ON RASHI
Rashi writes that Nadav and Avihu were already Chayav Misah due to Chet ha'Egel. But R. Eliezer says that they were liable for ruling in front of their Rebbi?