Checking the history and upcoming launch list at https://www.nasa.gov/directorates/heo/home/CubeSats_initiative , it does not look like the ELaNA launches occur in numerical order; I will guess the ELaNA number may be in the order contracted by NASA with the launch provider, but it has no bearing on when a launch may occur.  And I'm not surprised if there are restrictions on what ELaNa customers can say regarding schedule.  The critical date for AMSAT's engineering is when Golf-T has to be delivered by AMSAT to whomever is responsible to NASA for integrating all the ELaNA payloads into the payload adapter and launch vehicle.  All the development, integration, and final testing of Golf-T will have to be finished before that date.  Lots of things can happen between delivery and launch to change the launch schedule, and secondary payloads don't get any say in that.