Missling mentioned several times that seeing improvement in the RETT adult population bode well for the pediatric study. He stated several times that it was difficult to see improvements in Adult Rett patients (which we presumably did), therefore implying that seeing improvements in the pediatric study was a smaller hurdle to clear.
The law firm filing first is likely not deeply in to biotech understanding. It doesn't matter too much at this stage. Pay attention towards May 14th as the lead plaintiff deadline expires for more thorough worked out motions for lead plaintiff from other law firms. If there no additional law firms with a plaintiff joining the case, then that would also be a signal that the case is unattractive.