Although your upset about her not inviting your mother and not even talking to you about it first, i don't think you can say anything to her. I wouldn't take it personal. Even though she invited 200 people, sometimes that still isn't enough to include everyone you want to. I know i had to invite about 60 people who i have seen maybe 5 times my whole life because it's my dad's family maybe she had some pressure from her parents and her fis parents on people that needed to be invited. Plus maybe if she invited her mom than there are 10 other people that she would feel like she should invite. It really does add up and sometimes you have to make cuts even if you don't really want to. I'm sorry, i don't mean to be a debbie downer.
But i do agree with the previous post, if she's been slacking on the moh duties than you can definately talk to her about that.