"Formal night" is now "hey here's a chance to dress up and get photos taken before or after your meal" night.
Wear what you want (without looking like you came right from the pool)
You don't need to contact special needs for gluten free. That diet can easily be accommodated just by visiting the MDR when you board and speaking with the head waiter to note you needs on your dining profile and just remind your waiter when you eat on the first night.
Windjammer will have a GF section. And never hesitate to ask if there's something you don't see (like GF bread). They have it.
The woman must have (very innocently and most certainly not intentionally) been doing something while swimming that set off the shark. Shark's don't just randomly attack.
Talk about wrong place, wrong time.