Shawna,
Looks like Otto was a career Navy man which maybe cause of the lack of census records, Your best bet would be to get copies of his Navy records. The death index for California shows his mothers maiden surname was Mayer. A copy of his death cert. may also show some info you don't have. I also have a Leu in my family tree but don't think there any connection. Good luck with your search.
Don Burns-in California