Our 27 yr old married SD brought up idea of a surprise party for her dad for his 50th. Her half sister, my BD aged 11 was thrillled and excited to plan with her big sister. SD texted ideas etc.. I finally emailed SD on logistics as my 11 year old of course, has not income. I took a huge paycut and SD makes more then us now after obtaining her Masters Degree we helped finance (along with Bachalors and Marrage and new car) Note: SD moved in with us when my BD was 1 and she was 20 in order to get as much as she could from us , apparantly, from what I am later told. Prior to this SD lived with her mom and moved all over world with military SD. Over summers since she was 3 she visited us and I was the mom figure when here, but she has a good relationship with her BM but prentends that she does not .. she has multiple personality disorder I sense trying to love who she is with but actually hating me and my daugther:
She has done hurtful suttle things to my BD and now it all is coming to a head:

Here is why:

Since she lived with us she had a journal for a sorority that had things in it that got back to me frm some of her "sisters" that ultimatley we read due to the extent of lies and scary topics of hate she had within. It had stories that were not true. This caused me to be fearful of her apparant jealousy and hate of her baby sister and blame for me breaking up her parents. (note I didn't meet her dad until they were divorced for 2 years which she admitted she knew) . Alsi lies of me calling and interferring with Dad/Daughter dates, that never ever happneed.. It was like she was creating a fanatsy world to these people, to make me evil when on the outside she called me mom, always said "love you" and played me for a fool. Meanwhile w/o knowing we saw the journal she puts on excellent charm, got free collage, new car and wedding over past 7 years living here. Now she is married, just had a baby, and has had her 2x divorced mom visit often.

All year she mentions idea of surprise party for her dad to my 11 year old as something they can plan together. I email on when/where, costs and venue as out of town people s/b invited and it is a month away and during holidays. She freaks at comcept of me not paying for this party. I reply, with how well her and hub are doing, thought they were hosting / paying since they had idea and in adult position now. Note, We have paid for every graduation, dinner event etc. forever, and ever and now after layoffs they make over 50,000 more then us. So, she calls daddy, tells him I put strongs on all the gifts they got foever and showed him email about the party. He has been sober for many years and almost lost it.

Do I invite her as me and 11 year old are moving forward with party as my 11 year old wants to and he deserves it.
DH said don't call or email her as she is a troublemaker. But others say it is his daughter, he'll cool off, invite her.
I know she will ruin the surprise again or show up and cry in corner and be the victim as usual... I gave her uncondiational love but remembering the lies in journal that I forgave that she blamed on her mom putting in her head, and now this, make me want her to move back to Kansas!