The Jacksonville, Florida Public Library website has a nice set of local city directories. Most of the years between 1891 and 1925 are either scanned in and browsable, or 'under construction'. When a year is selected, thumbnails are loaded for every page, which can take a couple minutes, but then it is very easy to browse through the directory.
There were no Van Everys in the 1916-1920 directories, neither my great-uncle Samuel, nor his alleged wife (see previous entry). Of course, her letter in his FBI file only said they were married there, not that either of them lived there.