Who was "Yahdai"?
'Rashi': He was one of Eifah's sons. His father is not mentioned 1 , for there was no need to mention any other children of Eifah other than him.
Radak: He was one of the sons listed in the previous verse; he had two names.
Vilna Gaon: He was Gazaz' son. "U'Vnei" applies to also before, as if it says u'Vnei Gazaz Yahdai, and below, "u'Vnei Yahdai Regem?"
Malbim: He descended paternally from Gazaz. The great Sefer of lineage had every step in the chain of lineage; Ezra included only what was known and relevant in his time.
'Rashi' implies that Yahdai was a son of Eifah, but not [necessarily] from Kalev. Perhaps this is why he was not taught with her other sons in the previous verse! (PF)
