But how would one deal with specific plugin options?
Like when copying the post, we are adding a canonical option to the post, so it always refers to the original Discourse post And we are linking WordPress post with Discourse, to show original comments, and other options.
This sounds really complicated. Why are you cross-posting to WordPress, but keeping the canonical URL pointed at the Discourse topic? It would be vastly easier to just link to the Discourse topic in a WordPress blog post.