I have not read the other posts so forgive me if you've moved on from what I am saying here.
1. Where are you located? I can't imagine a mentor being the one to direct you on maternity leave. that should be standard, IMO. I don't know why maternity leave is negotiable.
2. You asked about her being passive aggressive. IMO, you are, too. You asked if SHE would like to meet. She doesn't nee to, but you do. Why didn't you asked her if you could meet with her? If you want to meet with her, tell her you want to meet with her. Don't ask her if she wants to.
Anyway, I'm sorry about your miscarriage, and congrats on your pregnancy
That's great news!
And, after reading more of the info from your posts, I'd move on from her. She seems flaky to me.