How to provision custom document templates (and content types)?

What is the recommended method for provisioning document templates? 

Is any of these methods possible/preferred:

- Content types in PnP Template: can a content type definition include a custom document template? Where and how should the template file be uploaded?

- Content type hub: is it enough to reference a published content type in the PnP template using the ID of the published content type?

- The "new" template feature, Announcing new file template management for document library: is it possible to add this kind of template using PnP?