What is the significance of the statement "Vayasimu es ha'Chalavim al he'Chazos"?
Rashi and Ramban #1 (on the Pasuk in 7:30): After waving them, the Kohen placed them into the hands of another (third) 1 Kohen, so that the Chalavim were now on top.
Ramban: The fat-tail and the kidneys now lay on the chests, with the Chalavim on top whilst they were burning, and it is Derech Kavod to burn them when only the Chalavim are visible.
Why did the Torah mention only the burning of the Chalavim on the Mizbe'ach?
Ramban, Moshav Zekenim: Because they took up the major part of the burning.