the followup research questions could be better suited for an afternoon rather than a PhD

Could they? Very well! I hereby request at least one such research question in a future week, marked as such, for comparison to the grander-scale research questions.

An online meetup might be nice, but I'm not confident in my ability to consistently attend at a particular time, as evinced by my not generally participating live on Monday evenings.

Interviewing a relevant expert is useful and related, but somewhat beyond the scope of a reading group. I vote for this only if it suits your non-reading-group goals.

Multiple choice questions are a good idea, but mainly because taking tests is a useful way to study. Doing it to gather data on how much participants remember seems less useful, unless you randomly assign participants to differently arranged reading groups and then want to assess effectiveness of different approaches. (I'm not suggesting this latter bit be done.)

Thank you for the examples.