Am I being maid-of-honor-zilla?

I'm so sorry that you have to deal with this. I had one girl as a bridesmaid in my wedding who was a teenager and she did better than this! You are doing such an incredible job that I bet the bride is thrilled! WOW - I had a friend like that who had to take over the Maid of Honor duties and she did all kinds of things like you did and even managed to work things out to make even my in laws happy with the bridal shower and everything. This one bridesmaid is the out of control one here. She can't stand to be told what to do - but she has to get over herself for the bride's sake. So, what you need to do is tell the bride that you are going to use her name in connection with details. If they think things are coming from her and not you - then they can't get upset right? The other idea is to have your wedding planner or another outside person not related or friends between you all to provide instructions and details rather than you - that way if they are going to whine and complain - it won't be to you - because you shouldn't have to take that.