Should I give my niece her things back?

I (25f) have a niece (21) that was staying at home with me and my mom because she had troubles with her sister. Long story short, she has anger issues and my mom has very little patience. It all ended with my mom fighting with my sister and my niece leaving.

The thing that's bothering me about it right now is that some of her stuff ended up left behind. Nothing big; stuff like her shampoo, some food, a magazine, stuff like that. I think that what worries me is that she might come around saying that we stole her stuff or whatever, ensuing another screaming match.

I want this issue done and over with permanently, without any more drama. I was thinking that I could arrange a meet up somewhere in public, put her things in a bag, give them back and cut all communication afterwards, but I honestly don't know if she even wants anything to do with any of us right now. Is it really worth contacting her about these things? Should I let it be/wait until she messages me about it?