For what did Yehoshua bring Yehudah close?
Rashi: He cast one lot among the heads of the families, and afterwards among the Batei Avos (of the family caught), and afterwards the people of that Bayis.
Who was Zavdi?
Radak: He was the head of the Beis Av [to which Achan belonged].
Why does it not say va'Yakrev Es Shevet Yehudah l'Mishpechosav, like it says in the other cases (Yisrael li'Shevatav Mishpachas ha'Zarchi la'Gevarim
Malbim: Yehoshua brought the Shevatim one by one; after Yehudah was caught, he did not bring the others. Zarchi was the last family; none of the others was caught, so there was no need to bring Zarchi in front of the Aron.