OT: advice for relationship with stepdaughter acts like there is attachment issues?

Hey all,I was wondering if you had any advice for me in the way of how to act and/or respond. When I married S, I also gained a 23 y/o stepdaughter. S became right after high school and basically that relationship did not last. From stories I heard (and this is just his family’s side, so take with a grain of salt) she was very violent and went after him with a knife…so yeah sounds like a warm fuzzy relationship. When he and his daughter’s mother parted ways, he tried to have visistation and weekends, but I guess it was very contentious and court, and false starts (he recalls A’s mother coming to drop her off for a weekend and then snatch her back in the car and drive off while A is screaming wanting to go with ‘daddy’….just bad back and forth stuff like that). It was so bad that S decided he didn’t want that trauma all the time so he paid child support and saw her when he could (he regrets not asking for sole custody or joint, he was brought up thinking all kids do better with their mothers….especially since his own childhood was dysfunctional but his mother was good).Fast fwd. to when he was married to his late wife, his daughter was dropped off at their porch with mom who told him his daughter was of the devil and she didn’t want anything to do with her (13 year old here now)….so she lived with them for 1 year but couldn’t handle the different structure and rules and ran away at 14 and ended up in and out of juvi and missed her stepmom’s funeral and that messed her up more because she did have a connection with her. So A has been in and out of juvi and jail since the age of 14 and demonstrates attachment issues. She has a relationship with her dad now, my husband (even though it seems more manipulative or a 'what can I get from my dad' type relationship), however, she lives 2 hours away and S says that in his professional opinion, that is for the best because she has a rough time with authority and is unable to live in a typical home….and as a father it kills him because sometimes she doesn’t make great life choices in places to live etc. This is the longest she has been in a school program (estetician, hopefully she can use without her felonies coming to bite her in the butt) and so we both are hoping she gets her certificate. Here is where I could use advice. Since S has proposed to me, she calls me by my name, but every now and again she calls me mom. Ummmm not that I want animosity between her and I or her to treat me or my child badly, however, I’m not sure it’s normal for a 23 y/o to call her dad’s wife who is only 12 years older than her mom. She emotionally acts and makes decisions like a 13-14 year old. She wants to be close to her own mother but years of abuse and abandonment make her relationship with her mother kind of weird. It’s just weird. I’m nice to her and ask her about her life and her aspirations are, but I end up not believing anything that she says, I’m uber careful with my daughter, and S supports me in that, he’s caught between seeing her as both a father and as a professional that deals with clients on parole/probation with behavior/personality issues. A treats my child nicely (and again, I don’t want ill will….) but I just think she has attachment issues…..now she is an adult so she does not live under our roof, and S makes sure she has a roof on her head by paying a room for her if she finds it (she’s moved so many times….mostly the places she finds are rooms for rent for $100) and that’s it, because he doesn’t want his money going to illegal activities if he can help it. Any thing I should be aware of? Boundaries out in the open or just between S and I? Is it different because she is not living with us so our minor interactions (a couple hours every other month….if not in jail) probably won’t bring up issues? This is just new territory for me and it seems very attachment related….any words of advice or wisdom…or btdt with grown stepchildren would be very much appreciated.