The list you have just created already contains important elements for the data protection information for your event. You should make the data protection information available to potential participants as early as possible and, to be on the safe side, display it again at the entrance to the event. 

You have thus fulfilled your duty to inform and all potential participants have been informed in advance about possible image and sound recordings. As long as participation in the event is voluntary, everyone can decide for themselves whether they agree to the recordings or otherwise stay away from the event.

Source: OpenClipart-Vectors on Pixabay