I was very apprehensive when my D17 was transitioning back home after an 8 month residential stay. I share in the fear you are feeling too, still do as she's only home 5 months.
Be proud of the progress your family has made, her being sober for nearly 6 months is tremendous. It sounds like the case manager has a plan in place with contract and clear rules. Remember to hold to the rules and not allow them to be bent, that is where the manipulation will begin. I needed to take her return in small steps, not thinking of tomorrow, but staying present in the moment. Using the tools I learned along the way and reminding myself to listen, validate and not be overbearing (big downfall of mine).
We continued with family weekly sessions and have become stronger. There will be missteps (mistakes), what I have done is my absolute best to not fly off the handle, but to listen with empathy, validate and have a conversation w/good tone. We are all human and mistakes will happen, I've done my best to apologize if I'm in the wrong, have a calm discussion if she is and most importantly, move on instead of continuing the bicker/fight.
Good luck with this next step and stay present, don't worry about tomorrow. You have come a long way, be proud