OK let's discard scenario #1 because you obviously want to party your hiney off this weekend.
Since you have no control over #2 it seems to me that #3 is your best option. Go with your friends. Take a date of your own. If you go and see exxie there be civil and say hello if you are in close proximity, don't bristle at her date if she has one, it's better to smile at him and then move to another part of whatever bar you are in. Have a good time. Don't pay too much attention to exxie. Have a good time. Don't stick around to see how long exxie stays...unless you are working on a good prospect. If she leaves early stick around. Something good might happen. Don't drink a lot to impress or punish anyone I have tried to punish other people by over imbibing and I was the one who suffered
The other option you listed is "stay away from the situation entirely" to which you forgot to assign the number 4.
If you think it's going to make you feel bad to go, don't go. Exxie won't care one way or another and if she does you don't care because she is your EX!
Well here's another idea: #4a !!! If you have absolutely no moral obligation to go to any of these festivities screw it! Go have a kickass good time elsewhere far from the entire scene. Pick up a girl or two or three.
There is no reason to subject yourself to suffering.