Just my personal observation when doing demos is the quicker the project the more you will hold their attention. What I mean is that if it takes a lot of steps, some of which they may not understand why you are doing even when you explain why you can lose their attention. When I demo I usually keep keep s-hook stock cut to size and ready to go so if I see folks heading my way I just stick it in the fire and by the time they get to my forge it is almost up to temperture. With simple s hook they see a lot of the skills you use on larger projects and it happens fast. Tapering, rounding on horn or turning hardy, reheating, squaring and twisting if you like and then repeating it on the other end to give a functional item. Another idea would be a a rough RR spike knife. Doesnt have to be to completion but they can see you go from something they all can recognize and watch as you change it into something else.
I also make a very small butter knife/letter opener out of 1/4" stock that people like. It is fast and keeps their attention.
People also like to see you finish items with beeswax it is fun to watch the watch smoke up and sometimes light on fire and they can smell the sweet honey like smell.
Tell us how much time you are expected to demonstrate and others will have other ideas.