Assuming you mean the lone Maid at the Beauregard Estate in the east swamps, no, you can't recruit her.
Breaking the headstone is entirely up to you, but there are consequences regardless of if you do or don't. The same is true for all the headstones you can make that choice on.
If you mean the blue-haired Maid you run into on the east swamps region map that eventually goes to the Edgerton Estate in the north swamps, then what
NotthingMuch said.
Well, I have good news and bad news.
The bad news is that I found more issues than just with your Task List and I have no idea how they happened, except for one instance of missing Task List update commands. Those things most likely happened because you moved switches and/or variables you shouldn't have, but since I can't find the exact cause, I can't be sure. Even bugfix features I tried to use weren't working for you for reasons I don't understand, which isn't great for a few reasons.
The good news is that there's nothing stopping you from continuing on, I've fixed your Task List, and have attached a fixed save.
And if you need the reminder and the Task List isn't helping; your next step is to go to the Ambrose Theatre.