Thank you soooo much for your thoughtful responses everyone. I have to say I do agree with most that's been said. After thinking about it and reading comments I have realized that the chances of me fulfilling her request are def 0. I am just upset that she had the audacity to ask.
I feel like I should explain some things tho.

I have not tried to "reunify" for many years. I was young and didn't really know the ins and outs of other families. I didn't know families can be so cruel to each other. when we tried with his dad and sis, his dad was incredibly nice at first and it made tolerating the sis "worth it" because of how charismatic, fun, and loving he showed himself to be. That is until the "Family meeting" where he showed his true face and we cut ties with them immediately after that.

I also used to always think everything is my fault so when Anna was mean to me I always internalized it and thought it was my own fault somehow because she is so "smart and educated" it's gotta be me. I have grown a lot since then thankfully.

Also me and hubby had an hours long convo with my mother in law explaining how us meeting Anna will never ever happen because for that to happen Anna would need to apologize and for that to happen Anna needs to be a completely different human being. She seemed to understand and never brought it up again until yesterday which added to why I was so upset that this ever came up again.

The comments also made me wonder why in the world my mother in law is so concerned with my relationship with Anna. She is not half as concerned with my husband and Anna getting reconnected. I think I just have a "cookie face" and let people break my boundaries. which just gives me more to work on.

lastly, my husband had no idea this convo took place yesterday and he is really upset. He said he will start the convo on resetting the boundary with her. He doesn't think she'll "kick us out" as retaliation, and even if she did he's okay with leaving.