1)
What are "Mechim"?
1.
Rashi: They are fat. It is an expression of Me'ach.
2.
Radak: They are sheep with marrow and fat.
2)
Why does it say "E'eseh"?
1.
Radak: This is like "va'Ymaher La'asos Oso" (Bereishis 18:7, to slaughter the animals).
3)
What is "Ketores Eilim"?
1.
Radak: It is Haktarah (burning on the Mizbe'ach) Chelev of rams.