5.5 gen do not exist it is an arbitrary name for the capability I described. Lastly we don't know if NGAD will be 6th gen as we understood the word. For all we know they called B-21 6th gen.
The existence of loyal wing man drone needs to be defined yes. At the most basic level it can function autonomously for reconaissance even a J-7 could get one. But that is not what I refered to when I say compatible. I expect a much deeper integration than that. It may or may not need another pilot to command the drones giving complex orders. To do so a series of training, compute power, and software must exist on the aircraft to optimise the command power. I suspect latest twin seat J-20 had it in mind when designing it.
That actually brings the question of how much of a tech leap is a 6th gen air craft compared to 5th gen? The gap between 4th and 5th gen is huge because of a fundamental focus on stealth with internal bays. That is the defining characteristic of 5th gen. There are other capabilities that could also be considered as part of 5th gen like super-cruise, networking, sensor fusion. But even 4th gen aircraft can have/already does have those capabilities by upgrading their engines, avionics, computers and so on. So they are only secondary capabilities of 5th gen aircraft.
Compared to the 5th gen what will be the defining characteristic of 6th gen? Just the fact that it will not have vertical stabilizers? but even Yf-23 did not have a pure vertical stabilizer.
Other than that, everything else can be easily ported to 5th gen, even 4th gen fighters.
loyal wingman drone? Even 4th gen can control those
More networking? 4th gen can do it with minor changes
Optional pilotless flight? 4th gen can do it again with minor changes
It seems other than improving stealth more by using even more stealthy shaping in the front and back, the 6th gen aircraft does not have any other defining characteristic. So, 6th gen it seems is a more incremental change compared to the game changing nature of 4th to 5th gen transition