Wow, that is a lot of Drama! I agree, this day is about you and your FI. Make it clear to everyone that it is your day and whether they take part or not it is their decision but you do not need all of this. They are not in Junior High. Let them decide> I wouldn't worry about it. I have done that in the past for parties and people usually show up and act civil. I told them too much drama for me and they can deal with it and it always seem to work out.