For context I am Canadian and these things happen differently here than at home!
DS is turning 3, we're having a party for him from 1-3 at a sort of community centre that has toys and a play ground. Doing a jungle theme (not really). I bought little jungle themed picnic boxes for the kids (about 20 ish, it will be hell!), in each of which I will put a juice box, a pack of flavoured rice crackers, a few chocolate coins, a pack of freddos, and four sandwich halves (one ham & cucumber, one tuna, one cheese & tomato, and one jam). I will also put a box of crayons and a little colouring book, and give them cake and and animal mask and a huge animal helium balloon instead of party favours (hate the tat).
I thought that would be a fun way for kids to have lunch and also easier than bringing a whole bunch of plates / cutlery / etc.
All that to say- do I need to provide anything for adults? Can't really afford to feed potentially 40 adults!!! Xxx