I have no preset notion in mind for what type of music is suitable. All I ask is that any lyrics are family friendly, i.e. no adult topics and keep the expletives to a minimum. So techno is fine as well. And thanks Robin. 
By the way, the choice to use the previously released stuff is more of a brand management thing, i.e. in spite of the fact that we (Sound of Humanity) are partnering with the local municipality and the local arts group (and, as such, I have to list them as partners in the event) I do not want anyone to forget that we are the ones responsible for this event. I’m hoping that this will help us considerably for future endeavors (esp. in getting media coverage) and will also help us expand Foodstock to be an annual thing that can grow to eventually (my hope!) include subsidizing the travel cost of international act(s) to play live.
I can easily see, as an intermediary step, having a decent midrange video / audio setup somewhere in a studio in the U.K., Europe, etc. and have it streamed live to a large projection screen on the stage next year.