#Do you have a large format camera?

If so, set up a studio portrait area, pre-lit etc but let them click the shutter to photograph each other, or whatever else they might like **on orthochromatic film**.

Then you can develop the negs in trays under a safelight, just like you were planning to do for paper, and make contact prints with them after lunch.

If you use the enlarger for your light source, you can still show them how to use VC papers, and quite a bit of dodging/burning is still possible with contact printing.

So best of all worlds (given the constraint of one day and nobody has any cameras yet) -- no dark-dark room is needed, they get to develop by film by inspection, with all the magic that entails -- and also make some lovely little contact portraits of themselves to take home.