Not sure but I think in the spreadsheet documentation is a missing information to get a list-feed ordered by another column.
I tried following protocol example and get ordered by row number instead of lastname? https://spreadsheets.google.com/feeds/list/key/worksheetId/private/full?orderby=lastname First additional column information like column:lastname sort this feed correctly. What's about more sort criteria f.e. first by lastname, second by firstname ... ?
