Thank you, everyone for all of these suggestions. We were able to shift the focus a little in the context of of the planned agenda; we spent a long time talking about gearing, like DH asked "What's your most important gear?" There was one person in each session who said "the lowest" and we went from there, talking about shifting to get up a hill, how beginners run into trouble, etc.
I also was able to give a perspective on starting with clipless pedals, from someone who is not that coordinated, which several people thanked me for.
I am exhausted from talking all day and my feet hurt from standing, but this is the one volunteer thing I do that I actually enjoy.
Now for the beer and ribs later on...
2015 Trek Silque SSL
Specialized Oura
2011 Guru Praemio
Specialized Oura
2017 Specialized Ariel Sport