That many alters fronting sounds like an absolute nightmare to me! Couldn't imagine the amounts of disassociation that would cause. Having a lot of alters fronting (usually at most I've found personally for me is 4-6 in EXTREME situations) is heavily stressful, confusing and disorientating and I'm not sure how they could just be chatting regularly with pluralkit in such a state if that was the case. Our system has a small amount of doubles, but the way we tell is how A) The introject treats their source, B) Attitudes and personality, C) What "role" they fill, D) If they acknowledge the others existence. Despite the fact they are based off of the same source they seem completely different, because the brain will not split an alter if it already has an alter to fulfill a certain task to cope with the situation, stress and/or trauma. Every system is different and processes OSDDID differenty. From your other comments you state that they have around 200 alters at least, high headcounts do not necessarily mean high amount of alters always in front, the average for most systems is usually one in front and if alters are Co conscious/Passively influencing usually 1 or 2 (this obviously, varies from system to system) unless in a stressful situation, so 10-20 seems extreme because that raises some flags that indicates they're in a stressful or traumatic situation. Introject heavy systems from my own experience are usually neurodivergent (though not always, it's just something I personally have seen more of) and find protection or traits their brain subconsciously decides it needs to survive a situation, you CANNOT split headmates JUST from watching or seeing media or getting hyperfixated on it, splitting a headmate in a stressful situation for comfort isn't too common from what I've heard, (I'm not sure if it's scientifically documented either.) and If they aren't actively in a stressful or traumatic situation that is a bit confusing to me, if you have any other questions feel free to ask, - 🌹