Myermay I feel for you. I have a similar problem but the other way round. My dh's family are perfectly sociable, normal friendly people. My family are sociopaths. (Well, my mum and my dad). My Mum and Dad are divorced and never speak so I have to carefully plan to avoid a meeting between them.
I'd love it if everyone could just get on but it doesn't work like that. I think you should invite who you want to invite, when you want to invite them, and they can sort out their own difficulties. Don't take their problems on board as you have enough to think about.
I'll endeavour to take my own advice now. I know it's far easier said than done.
Good luck.