<human>: Give me the gist of the text in a nutshell

Hi everyone! I am a long time reddit lurker but didn't know where else to go with this issue.. I am really sorry about the text wall below...

My FH and I are super excited about our wedding next June (which we are fully paying for), but are having some issues with the guest list. Basically, as soon as we got engaged, my father (who hasn't talked to me in years) came crawling out of the wood work. He would just show up at my sisters house when he knew I was there and stuff like that. Now, basically to keep my sister (who is close to him and who I love a lot because she is awesome) happy, I invited him to the wedding with his girlfriend. As a guest. No walking me down the aisle, no father-daughter dance, just as a guest. 

But now, he is under the assumption that his girlfriend (who is a horrible person) is invited to our bridal-party only rehearsal dinner AND that his girlfriend's daughter (who I barely know) is invited to the wedding. It's 10 months before the wedding and I am so stressed about this.  My sister said to just invite them and not worry about it. My fiance said to not invite them and tell them to fuck off. I don't really want to do either of those. Help?
<bot>: Invited my very distant dad to my wedding to make my sister happy. Now he's inviting people to the wedding and rehearsal dinner. WTF?