User blog comment:KnocknickKnock/9 gates + master of the celestial realm/@comment-2.83.198.8-20131212210042/@comment-7418318-20131214085213

It was stated that SOME of the "lesser" constellation CAN have multiple spirits, not that they all do.

The only constellation that is confirmed to have multiple spirits of the same kind is the canis minor. Maybe the chissel too, but that's not sure, since it's possible that Katja got her hands on the key that used to be Angel's and on top of that it's not just from the anime, but from a filler-arc to boot.