1)
What is the meaning of "Yalok"?
1.
Malbim: [They hold water in their hands, and] slurp it with their tongues.
2)
Why were the ones who did not kneel separated?
1.
Rashi (from (Bereishis Rabsi Toldos): The ones who kneeled were used to kneeling to idolatry (Radak - Ba'al).
2.
Radak, Malbim #1: The ones who kneeled on their knees, they worshipped their reflection in the water (Yalkut Shimoni 2:62).
3.
Malbim #2: They kneeled to fill their mouths with water. This shows radical lust to drink [much] at once and weakness of joints, like the Akeidah writes.
3)
What should Gid'on do to the ones who kneeled?
1.
Radak: Also they were separated unto themselves.
