OTOH, the fact that I don't call afterward is considered a plus by most actors.
Turning this digression back to the subject of fan films, though - feed the cast and crew.
If you're not paying them and particularly if you're asking them to schlep a distance to participate, you need to do that much. IMAO. And there's a selfish aspect to it - bringing meals in keeps the production running on something resembling a "schedule" (hah!).