Papagena!
I am very happy that there was a shootout to the Magic Flute in the movie. When Stuart calls the hydrant Papagena, it's a reference to the fact that Papageno, the bird catcher, has been looking for his ideal mate, his Papagena, throughout the opera. And he does find her in the end, so they have a happy ending. There don't seem to be any female minions, so I can understand why a hydrant might appear to be one (there were also no female Smurfs until Gargamel created Smurfette, BTW).
Boo Hoo! Let me wipe away the tears with my PLASTIC hand!--Lindsey McDonald (Angel)