Good News, it looks like they'll only do One cut and paste attraction. Monsters Laugh Floor will be supplanting Muppets, but the other one will be an all new family ride. Which is a very good thing, because of the other Monsters Inc rides don't tickle my fancy. The look pedestrian by Disney's usual standard.
The recently added DVC booth's exterior will not change, except for its name on the front. Since it fits in with Harryhausens, it maybe changed to a new reservation booth.
Disclaimer: Everything I just mentioned is not guaranteed to happen. For now at least it has just been discussed behind closed doors.