1)
Seeing as the Torah writes that the B'nei K'has, the B'nei Gershon - (in Pasuk 41), and also the B'nei Merari (in Pasuk 45) were counted "Al-Pi Hashem", why does the Torah insert "be'Yad Moshe" only by the B'nei K'has and the B'nei Merari, and not by the B'nei Gershon?
1.
Da'as Zekeinim, Rosh, and Hadar Zekeinim (in Pasuk 22): Because, since Hashem commanded Moshe and Aharon to count K'has (Pasuk 1), it writes here "be'Yad Moshe" to teach us that Moshe was primary. It does not say before the command to count Merari that Hashem commanded it, so afterwards the Torah teaches that He commanded Moshe. Regarding Gershon, Hashem commanded Moshe, so it need not say afterwards "be'Yad Moshe."
