If she is going to be Celestia's successor, which makes the most sense and was the original intention, than she most likely get extended life. I'm not sure if that's still where they're going as the mythology has sort of been getting retconned into something much stupider. As much as I dislike McCarthy's recent writing, I feel a bit sorry for her for the crap she has to put up with, both from Hasbro and from the fans.
The toilet won't be leaving Ponyville? I didn't even know there was rumors about moving lavatories. That's a scary thought. My word! Glad that's not happening. That being said, I fail to see what another random McCarthy tweet has to do with anything. We weren't talking about Twilight leaving Ponyville.