This is a great analog solution!
Someday we might all have AI glasses that let you as the guide answer live questions, no matter where the attendees are: either a couple of people away from you (in a small crowd around the plant), or lagging behind because they’re still looking at a previous plant.
Another idea is to print out QR codes for the species that you anticipate seeing. People can scan these codes with their phone, and the code will take them wherever you want.
For example, it could take them to the “About” page on iNat, where they could click on the taxonomy tab, and then they might have a question like, “How do you know this is a member of Gentianaceae?” (or whatever plant family it is).