Add this to the list of spelling variants that I had never thought of:
Sonis for Louis
The “Iowa State Census-1905” database at FamilySearch contains several entries for the first name of Sonis. Based upon the actual card, I’m surmising that the intent was probably Louis, although one can easily see how the initial letter in this instance could be seen as an “S.”
Another reason to search databases using parameters other than the first name.