Panther suffers from anxiety and shows signs of PTSD. The time he spent alone in the forest took a huge toll on his mental state. He wakes up very frequently from bad nightmares and finds it extremely difficult to be left alone. Sometimes he feels like someone is pressing down on his chest, making it hard for him to breathe. Because of this, he has weekly visits to the tribe healer. His post traumatic stress disorder originated from the forest too- he often finds himself frozen in thought, reliving the cold, empty moments he remembers from the forest he was abandoned in. His time in the forest also stems a fear of squirrels (after a few weeks squirrels had begun to nibble at his skin).
Glowstik has struggled with bipolar disorder for his whole life. The highs are definitely very high, but the lows are almost unbearable. For years, Trixie just thought there was something wrong with him. She misinterpreted his depressive state for a teenage phase. Eventually, he’s professionally diagnosed with the disorder and Trixie puts him on all kinds of medications to “fix” her son. They don’t really help him at all.
Glowstik is magically transported to a different dimension where he meets the Regal Heir Dionysus, and finally starts to feel happy for once… he’s transported back to his own Equestria eventually, but the spell was hastily completed and had lasting side effects on Glow. He starts to hear voices that call out at him from all directions, but he’s unable to pinpoint a single one. Trixie starts to pick up the fact that he seems out of touch with reality, so she takes him in for another doctor’s visit. He’s diagnosed with schizophrenia and depression. He blames Trixie, lashes out at her and leaves the house for a few days, wanting to be as far away from her as possible. How could she force him back to this world and give him all these new issues to worry about?
Trix forces him to go back to school the second he returns to his “proper” dimension. He attends a prestigious private school that mostly consists of very rich unicorns, so he oddly sits out as the only batpony. He drops out at 17. Trixie doesn’t find out about it until a few weeks later. In his dimension, he really only trusts Lightshow, his sister, but even she can’t get him to open up. Glow spends most of his late teenage life feeling isolated and sad, wishing he didn’t have to be ripped away from the one pony he ever really loved.
Khaleesi has had obsessive compulsive disorder for her entire life, but it affected her worst during her childhood. She often found herself having to make things even- if she hit her left leg against the castle walls on accident, she’d have to hit the right leg against the same wall so that it would feel even. She also has intrusive thoughts and develops a habit of patterns that she must go through every day, in the same order, to feel calm. Celestia thought this was completely ridiculous, completely unaware of the severity.
Khal drops out of high school at 16. She never really even went to school anyway. Most of the time she’d clone herself and make her duplicate sit in class, while her real self was passing time in her dimension (she has her own) or sneaking off to go see her bestie Val. Celestia obviously didn’t approve of that, either, and frantically tried to persuade paparazzi not to write an article about the “Princess’s dropout daughter.” How embarrassing would that be for her reputation.
If things went a little differently in the timeline and Panther was never abandoned, these three would’ve been really good buddies. They’d start on the wrong path, vandalizing property and committing misdemeanors, maybe even serious felonies at some point, but through the counseling of Queen Cadence and Twilight Sparkle they’d be offered a second chance. They eventually would’ve become a night guard of sorts, a smaller, less famous version of the Wonderbolts, protecting innocent ponies from the dangers while they slept. In canon, Khal and Glowstik are aware of each other, but not necessarily good friends.