After i prepared everything for the Heist (sub/chooper) waited some days for a call from Wade. When he was not calling i tried with Michael start FIB missions at B icon. The first mission was started in Observatory and the second one you know from the trailer, kidnaping the witness from the skycraper. There first met all the protagonists and looks to me is the last u need to do before you can start the merryweather mission with sub in deep. When you finish 2 missions with B Wade will call you and H as Heist will show up on Trevosr second location by the beach.
The mission for me ended with no money but Wade got the chooper somewhere else and the sub is still on the airport so i expect new mission with new approach.