Hibiki concept:
The three Hibiki Curses:  I'd say that the assumption that Ryouga gets 
lost because of a curse on his family isn't uncommon.  However suppose 
the Hibiki family has not one but three curses.  Specifically: The 
Curse of Misdirection-geting lost, The Curse of Passion-a Hibiki's 
emotions are severely amplified, and The Curse of Strength-Why Ryouga 
is so strong, see the Waterproof soap story for a clue why it can be 
called a curse.  And it could explain why both of Ryouga's parents get 
lost like him.  In order to prevent themselves from crushing their 
spouses, Hibiki's always incorperate an adoption aspect into the weding 
ceramonies.  This transfers all three curses, but the curse of strength 
cancells out among the married couple.