This goes well beyond the existing one-box method, but it is theoretically possible to create a web archive of a tweet and replay that on a post. I wrote up some instructions on how to do this with plain HTML pages here:
Theoretically, one could write a plug-in to one-box for WACZ files in Discourse. Unfortunately, I’m more of a watcher of the project now since I had to shut down my Discourse-powered site. Happy to offer advice if asked.