Hotel
The Emerald Grande does not offer a room block, rather they just apply a discount if you give them Harris/Allen wedding. It is condominium with 2, 3, and 4 bedroom options that requires a three night minimum. If you're staying for fewer nights or require less bedrooms, there are plenty of waterfront hotels nearby.
Flight
VPS will be the closest airport to the venue. I'd also suggest looking at Northwest Florida Beaches International Airport (ECP), if you plan to rent a car, then this will be a good option and is only 1.5 hour drive from Destin. https://www.iflybeaches.com/
Travel Note
Transportation to and from the wedding will not be provided. We suggest using Uber or Lyft.