ghoul doesn’t talk with (or about) the other jokerz, much, anyway. the only one of his younger ‘coworkers’ that he trusted was woof, who he was already doing petty crimes with before he was ever hired by the joker. woof and ghoul keep in some kind of contact, though woof has it rougher than ghoul, given his appearance and lack of shapeshifting abilities. ghoul is very considerate of this and offers woof money or assistance when necessary. he’s a good friend, but a friend to few. he likes to keep it that way, staying distant from his human associates in his ‘day’ jobs, while still being friendly.
as i play ghoul in a more modern/au scenario (versus the futuristic verse he belongs in), harley’s grandkids are made into her nieces, and he is terrified of them. i headcanon that they’re still in the criminal world, though not in gotham. harley isn’t thrilled by that but what can ya do. ghoul does get along with harley better than joker and a lot better than her nieces, but he still avoids her when possible. as for other villains and so on, ghoul doesn’t trust any of them, really, which is why he doesn’t willingly work for them. he has a bad reputation in the villain ‘community’, as he is very eager (when under pressure) to give up knowledge about his teammates/job in exchange for not getting his ass kicked by someone (ex; batman). the only exception to this may be with his current job, as he respects penguin and also knows that penguin isn’t someone he can escape so easily. he may also act similarly with other big-name villains if they got their claws on him, since he’d rather not get on the bad side of particularly... influential people.
overall, he is uncomfortable at the prospect of having to hurt (innocent) people. when he was younger, he was more reckless and violent, mainly as a way to let out his own emotions, but as he grew older he became more mellow and his otherwise timid personality started to shine through. however, he had little that was redeemable in the human side of the world, as he completely tossed out his real identity and started from scratch. his only worth is as ghoul, where he can openly be a genius/crafty little bitch, which is why he chooses to go by that even in the event that someone learns his human alias or his real name. ghoul is who he is, not matthew or stewart.