1)
What is the significance that they were from Yehudah?
1.
Ibn Ezra: This excludes Binyamin; also Bnei Binyamin were in Yerushalayim.
2.
Malbim: The commoners are called Bnei Yisrael. Those from the Meluchah are attributed to Yehudah, the strongest among his brothers. Daniel was from Beis David, like Mahari said, unlike Ralbag.
