The funeral parlour provided tea, coffee, sandwiches, biscuits and slices at my grandmothers funeral. Not sure how much it cost...

I'd go for savoury options too - cheese and dip platter, cold meats/antipasto type stuff, sandwiches and wraps. Nothing too complicated to make or store. Many bakeries/delis do sandwich platters and even Woolies and Coles do antipasto platters. Just a note - no one ate anything cold after about 20 mins at my grandmothers funeral - think we were too worried about food poisoning from food out in the heat! Not sure if your guests will mind, but its a consideration...

As for afterwards, as long as you have someone to cook the BBQ, why not? Big bowls of mixed leaves, cherry tomatoes, fresh bread and butter and some prepared salads too if you like (potato, coleslaw etc). Even just tinned corn, beans, pineapple, beetroot in bowls. No one is expecting an elaborate feast, I'm sure.

HTH. Sorry for your loss x