One issue that comes up is the height of the iframe (may require scrolling or may result in white space); no easy solution around that. Notice that I centered the iframe (so, paragraph centered, then iframe in paragraph).
You can also have a dynamic widget for daily discussion prompts where there would be a new discussion prompt each day. This would be useful for the kind of discussion where students have a rolling period of time where they can contribute, but the daily prompt would keep it fresh. Again, alert students to clicking on more info so they can share the link to their prompt in the reply.
Here's a screenshot with the script for daily cat: