Try to place the hint, highlight and add also minLength: 1 instead of the first null, it should look like this:
$('#remote .typeahead').typeahead(
{
hint: false,
highlight: true,
minLength: 1
},
{
name: 'cast-directors',
displayKey: 'value',
source: castDirectors.ttAdapter(),
templates: {
empty: [
'<div class="empty-message">',
'No matching names',
'</div>'
].join('\n'),
suggestion: Handlebars.compile('<a id="typeahead" href="{{link}}"><p>{{value}}</p></a>')
}
});