The short answer is anything you like! It's a rustic outdoor wedding in July, so wear something that you will be comfortable in. For reference, the bridesmaids will be in mismatched florals, and the groomsmen will be in blue khakis. One word of warning: heels might be difficult in the grass.
The barn itself is air conditioned, and seating inside will always be available to anyone who needs it. The ceremony will be brief and outdoors. Dinner will take place outdoors under a shady tent, with a breeze coming over the hill.
Yes! The menu includes items such as seafood paella, smoked chicken, farm vegetables, and grilled fish, which are all gluten-free. For vegans, there will be smoked potato hash, red pizza, multiple vegetable dishes, a variety of pickled vegetables, dips, and "chicken fried" mushrooms (just ask the chef for the mushrooms). Sorbet and grilled stone fruit will be part of the dessert spread. There will be labels with allergen warnings, and the chef will be on hand to address any concerns you might have.