According to Jmanga's official Facebook page, Jmanga and Kodansha have teamed up to add several former Del Rey titles.
Currently they are:
According to a post on the official Jmanga Facebook page, more Del Rey titles will be coming in the future.
According to Jmanga's official Facebook page & Twitter they will be releasing all the formerly in-print Del Rey volumes and continue the series that had unreleased folumes
Sources: Feature: Kodansha Comes to JManga!
, Jmanga Facebook Page
, Jmanga Twitter Post