I think you have received some good advice thus far. In my opinion, the safest way to figure it all out is to have a chat with your FI. Figure out earlier on what you will do in case people you really want there can't afford it. For us, we were doing it no matter what. Some loved ones couldn't come and we were heartbroken. In the end, it was worth it though.
My guests all paid about $1500 per person for a week at an AI- including airfare. Everyone that went had an incredible time.