pass filter options to the plugins where you return the elements filtering by text and data-tag
try this
$('#livefilter-list').liveFilter('#livefilter-input', 'li', {
filterChildSelector: 'a',
filter: function(el, val){
return $(el).data('tags') == val || $(el).text().toUpperCase().indexOf(val.toUpperCase()) >= 0;
},
});
no need to modify the core plugins...