1)
Why does the Torah write "Pekudeihem" in connection with Gershon and Merari, but not in connection with K'has?
1.
Malbim (in Pasuk 22): Because Moshe, Aharon and his sons (who were from K'has) were excluded from the count. "Shomrei Mishmeres ha'Kodesh" excludes the Kohanim, who do not guard. It also excludes them from the next Pasuk; the Kohanim encamped in the east, not with the rest of K'has in the south.
