Recent personal experience of an actual Zafira rented from EDI for a weekend at a wedding: Four adults, four average size suitcases and an assortment of cabin baggage would comfortably fit.

But there wasn't a huge amount of extra space. We could probably have got in one more suitcase if some of the cabin baggage was distributed around people's feet. But, of course, having a fifth person in the car inevitably reduces the space available for that. I would have expected it to be pretty snug in that situation. Also the interior rear view mirror would probably have become unusable.