I am so sorry to hear about loss, especially your father so close to your wedding. I lost mine not too long ago it will take some time but with the support of your family and FI it will help.
Maybe take a bit of time talk to the guests that you really would like to have there and see what they could afford (I am sure they all could use a vacation). I really wanted certain people to attend our DW so we asked them what they could afford then selected a resort that fit everyone's needs. I am sure your FI will change the location to marry you! Then you can always have a anniv. or honeymoon in Hawaii. Good Luck on your decision!!