FDA rules dictate that its not impossible to have the FDA buy-in on new SAP/endpoints post hoc data collection, and data scrubbing after data lock but it is highly unlikely. Especially if the new endpoints are unusual/controversial to the FDA as you pointed out.
I'm betting on 5% AA and 95% on a P3 ADD trial. Having said that I think Anavex should count its lucky stars if they get the endpoints and SAP bought in by the FDA as presented in yesterday's (summarized) PR. IMHO