That's where I found why I couldn't search them out: they were transcribed as "Walter." Thanks to twitter, I found that I could click on "Flag for Review" under the "About This Document" sidebar to report the error, and the name has now been fixed.
But, this error gave me the idea to search for Walter(s) when looking for the Waters family. I've tried many different variations of Waters, but never this one. And really, you forget to cross a 'T' and it turns into and 'L,' which is an easy mistake. I don't know why it didn't occur to me....
Anyway, I've never been able to find this family in the 1910 census, so I headed by to Ancestry.com. I searched for: Lou* Walters (soundex), born 1881 +/- 5 years, all of USA. And bingo! The first result returned was Louise Walters, born 1882 in Georgia, living with Levert E Walters in Astor, Lake, Florida.
Happy Dance ensues!
So, thanks to an error on one census, I found a missing family in another. And there are quite a few clues in this listing that will help me in the future. For one, I had no idea they ever lived in Florida! Woot! Off to search for more.