My D is having her bday soon and I am wondering if we should celebrate it together or not. I am definitely doing something for them on my own and D and Dad time, but still not decided whether I will do a celebration with W together. The only reason I would do it if it might be better for D right now
Yeah, this can be a tough one. I think you are in the right place mentally to go either way with it. IE, you can invite her and not be upset if she refuses, and you can have a party with her there without it being pursuit behavior. So in YOUR case I think it's fine to invite her. I wouldn't say that to some others here just due to their emotional fragility right now.
In my case XW and I did continue to do the kids' birthdays and Christmas mornings together with our kids at my place or hers, and in fact we still do. Neither of us has brought an OP along though.