I’m not sure how this would help in my scenario.
My problem is that I have manually created Discourse topics for old blog posts and then simply put a link to the forum at the end of the post:

Obviously this is sub-optimal because it doesn’t show any of the comments on the blog and gives no indication of engagement.
What I hoped to do is install the WP Discourse plugin and use it for any new blog posts but also go back to old posts and manually link the posts with the forum topics with the hope that they would display the same way as any new post would (ie. showing the comments directly on the blog post). Does this make sense?