You’ve gotten a ton of great suggestions, and I see that my top “beach” element—straw bag, hat, or shoes—is already on your list.
Thinking of MsMaven’s husband, I think you should go the breezy linen tunic/dress and pants route, because it can fit in everywhere. If you wore the Breton stripes and most others were wearing adorable dresses like Aida’s, you might feel awkward.
Are you actually going to a beach event? If your ankles still itch from sand months ago, we’ve got to come up with something to protect them when you’re on the beach.
How about high top sneakers, a boho tunic, and skinnies, with a straw bag & hat?
ETA: Maybe she’ll want a total 180 from her first wedding and the theme this time will be Montecarlo or New York, New York!