The old IFR/VFR vs TOS argument. Mil tend to be more concerned about the service than the flight rules. As far as the specific trip you mention it was probably a VFR trip but the pilot will only file an abbreviated flight plan/booking out anyway. As for separation in the circuit you would sequence it the same as you would different speed acft in a standard circuit. If you were worried you could orbit other acft at the start of the DW leg and the FJ would turn inside. A FJ pilot should only break when he is visual with all other acft in the circuit. If they are in any doubt then they should continue through the deadside and go out for another join...