Board Thread:General Discussion/@comment-24679308-20140318211927/@comment-24676399-20140319014851

Kaien's body and likly his soul was still fused with that hollow bug thing that killed his wife when he died. After dieing his/that hollows soul went to Hueco Mundo where it was ate by one of the Espanda.

So no not the reincarnation they look alike because of being family.