The Hibernate Search Modules ZIP[1] should be a valid Wildfly Feature Pack[2]. This means changing the internal modules structures to start with /modules/system/layers/base/ or /modules/add-ons/hibernate-search/

[1] https://sourceforge.net/projects/hibernate/files/hibernate-search/5.6.0.Alpha3/hibernate-search-modules-5.6.0.Alpha3-wildfly-10-dist.zip/download

[2] https://developer.jboss.org/wiki/WildflyBuildProcess