Heroin addicts at our baby shower 😕

I have several members of my step family that are known heroin addicts. One of my other family members is not an addict, but it is kind of enabler of those addicts. She's a sweet older lady that has been a grandma figure in my life. I invited her to my baby shower, and then she invited her daughter who has been on heroin for about a decade. I'm fearful of her daughter (my step-aunt) knowing where I live, and also that she might steal things and just completely embarrass me while she's here (she's super loud/annoying) and we're pretty low key/normal people. 
I've told my granny of my concerns and she's not willing to talk to the addict and uninvite her. She says her daughter swears she is clean, but my sister (also an addict of 6 months, trying to get off), knows she is not clean. My husband is understandably freaked. On a side note, my sister is definitely coming, I still trust her (rightly so or not - that's a whole other drama).
The party is this Sunday. I don't know what to do. 😔 It's bad enough that half of my family is like this, but this additional stress is so unwelcome right now.