I would love her to be part of his inner circle. Her bio looks great btw, I feel so bad for her! But I think it will make her thrive here at the sanctuary, since like you mentioned, she's lived through worse for far less better reasons.
Her skills as a sniper would make her a great asset to Negan as well. He tends to like to do his killing close up and with an audience (because there's usually a lesson to be learned from it) but she would be very handy for regardless.
Also I like what you did there with naming her gun Stella.