Hi Ed,
The Freebase Suggest code is actually Open Source here: https://github.com/freebase/freebase-suggest/blob/master/src/suggest.js
But the Javascript code expects a Search service api that takes parameters. The original Freebase Search service api was a mashup of Lucene, Solr, Python and Javascript if I recall correctly from the Freebase engineers discussions on the old mailing list. Anyways, Wikidata or yourself would have to create such a service. But it looks like one already exists that powers Wikidata's Search...its just not the best and it needs token refinement and other stuff from my experiments with it.
Magnus Manske has done a reconciliation service for Wikidata https://github.com/OpenRefine/OpenRefine/issues/805#issuecomment-228551530
Thad +ThadGuidry https://www.google.com/+ThadGuidry