In May 2014 we were in WDW when SDMT was opening. Official open date was announced as May 28th, at the beginning of May I was able to secure FP+ for May 29th. About a week before official opening they were running people on the ride in spurts. I believe we were able to ride a day or two before official opening day. People on this board will post if/when they start allowing people on. We are at WDW May 19th-26th, so I am hoping for the same luck with FEA.