Come on Unicorn, you KNOW the answer..... HONESTY is always the best policy especially in dealing with mature adults. This is NOT a kids party, and it appears from all your stories that you are a man of means, so WHAT could you possibly need that you cant provide for yourself ?
And for many on the guest list, shopping for gifts can be puzzling or time consuming and might might appreciate NOT having to.... The point is to celebrate with caring, loving people who have place in your heart and life....
So TELL THEM no gifts, and "get your party on"..... then if they choose to, they can bring a little "hostess gift"... like a "bottle"..... which you can then SHARE with them.