With Docuss, your Wordpress blog would be displayed, without its header, in an iframe in your Discourse instance. There would be a unique Discourse url for each Wordpress page.
Similarly, the Mustacchio demo shows a static website integration:
- Mustacchio demo (static website displayed in an iframe in Discourse)
- Original static website for the Mustacchio demo (without Discourse)
In your case, the static website would be replaced by your Wordpress blog (without its header).