Use iMovie on shared iPads without Apple ID

I have a set of iPad Mini devices (wifi only) that need to be used in workshop settings, by different users each time. I have downloaded Apple Configurator 2.6 and used it to do a basic update to iOS 11.2.6 and setup - but it's not possible to use iMovie without setting up an iTunes Store account and an Apple ID. Setting up and managing multiple Apple IDs for each iPad is going to be a nightmare - how can I use iMovie without this? I thought iMovie was free with the iPad? Any help appreciated - thanks!