What are "ha'Alafim"?
Rashi: They are (Malbim - big) cattle. Radak - this is like "Shegar Alafecha" (Devarim 7:13).
What are "Ayarim"?
Radak: They are young donkeys. Malbim - they are not needed for Avodah as much as cattle.
Who are "Ovedei ha'Adamah"?
Radak: [Animals with which] people farm the land.
What is "Belil Chamitz [Yochelu]"?
Rashi: This is like "Al Belilo" (Iyov 6:5), straw that fermented and is strong via the grain inside it.
Rashi citing a Midrash: Belil is an expression of Balul; food is mixed in the straw.
Radak, Malbim: Amidst abundance of grain, they will feed to the cattle and donkeys fodder that they cleaned for them 1 . They will winnow it, like is done for what people eat. Belil is fodder, like "Im Yig'eh Shor Al Belilo." Yonason translates Chamitz to be fat.
Malbim: This will be amidst great Brachah.
Why does it say "Asher Zoreh va'Rachas uva'Mizreh"?
Rashi: The grain is winnowed twice - once with a shovel, and once with a basket, in order to clean it. Radak - the root of Rachas is Ru'ach, because they winnow in the wind, and it cleans the (removes) the chaff from the grain.