Freemarker templates for Essentials features in webfiles use Essentials classes, for example org.onehippo.cms7.essentials.components.paging.Pageable in the site/freemarker/hstdefault/newslist-main-newslist.ftl.
These classes are not a dependency of the webfiles maven module, so content assist for these objects is not available. Also the @ftlvariable at the top of the template results in an error for that template when using Intellij (see screenshot).
The problem can be solved by adding this dependency to the webfiles pom:
I don't think it should be part of the archetype, but better be added by Essentials when needed.