1)
What is "Shulchani"?
1.
Radak citing Targum Yonasan: The table of Lechem ha'Panim.
2.
Malbim: Shulchan Hashem is the privilege to eat Kodshim. One who does not serve, he does not eat Kodshim except for a Ba'al Mum. These Kohanim will guard Mishmarti, unlike the first ones, who guard only Mishmeres ha'Bayis.