Okay, it seems like you do not have to do, all this.
You do not have to be the "neutral" one here.
Why don't the others take the lead too?
Then, you are all, attending an all nighter for a charity event. That is a lot on your plate.
Your Husband and kids, just want to have a good time.
So, THAT is the priority here.
Not being the ONLY people pleaser, in the entire antagonistic family.
You either take on that "role" or not.
Your choice.
And your HUSBAND can take it on too. Not only you. Or just him deal with his family.
Personally: well things are not real peachy in my family. We typically all go to my cousin's house for Thanksgiving. BUT this year.... because of all the pain in the rear problems, in my family, we are not going. We (me/Husband and our 2 kids) will be doing our own thing.
I spoke with my cousin personally (she is a real great gal) and I told her graciously, that we will not be attending this year. She got the drift, she knows my family (namely my Mom and siblings) is difficult, and she could fill in the blank lines herself. But she said that if we change our plans, we can still go to her house. She was real gracious.
So anyway we are not going the "family" gathering this year.
And, also because, my Husband... puts up with a LOT of irks, with my family, and it is hard for him. So, as his Wife and per my own wishes too... we will be doing our own thing. ONLY us, me/Hubby and my 2 kids. We talked with our kids about it, and they have no problem with it. They are 6 and 10 years old.
Personally, if I were You: I would NOT do this nor host a meal for all of them. And since your extended family... is so.... ill behaved and full of bad attitudes... even if you host this gathering... there WILL be problems and since you are the Host, you will probably, be "blamed" for anything that happens.
The bottom line is: you will be blamed if you don't Host. And you will be blamed if you do Host. So just do what YOU and your Hubby and kids want. With your own family.
You cannot please... those antagonistic extended family, of yours.
They will never be, pleased.
Those are their problems.
Just tell them ahead of time, you will not be hosting anything.
Don't inform them at the last minute. It is next week, already.