Where to stay is a big question to ask. How many people and what type of experience are you looking for? There is the classic corporate resorts that have over a hundreds of room, to the small Inns and guest houses that only have a half dozen rooms.
My personal opinion is to start off with the smaller local owned and managed properties. The guesthouses, B&B’s and Inn’s are the first place to start. The second avenue is the vacation rentals operated by local real estate companies.
The last choice is the air bnb’s and vrbo’s and other home rental web sites. Key West has a strong transient rental law. if they don’t have a license to rent daily then they can only rent a house basically once a month up to 12 times a year. There are people that will put up a scam listing for a house to rent,they get paid upfront and the people show up to discovered that they don’t have a place to stay.
The big resorts and hotels, if your a small group for wedding or other event is that your just a few rooms in a large building. Unless you are paying big bucks to have the wedding on their property. It is possible your not going to get the service or attention you deserve for your special day.
If there is any questions you have check this city site out. https://www.cityofkeywest-fl.gov/856/Map-Addresses-of-Transient-Rental-Proper