Having Melanie and Sara being incurable gossip mongers isn't helping the operation, they seem likely suspects for spreading rumours.
The girls aren't being forced, but their motivations differ, Riona does it to have a place to stay and support her habit, Camilla's motivation seems solely financial, Mona has the same motivation, Maya is absolutely clueless, Josy seems to be attempting to save Maya from herself using the fact she knows Tommy will do anything to avoid things getting back to his parents about his behaviour.
The whole being short and reckless expansion seems to indicate along with burning both Tommy and Dawe that she needs cash fast for something, that's gonna backfire spectacularly, I'll stand well clear of that, bad MC ending could be several years incarcerated as the fall guy or at least evicted from college.
Camilla may be in on it, you don't see her during the party when the cluck was posted which means that you have to suspect that she used the computer to post it and let's be honest with ourselves, how many of the Diks wouldn't let her post something on the computer prior to the incident to get in her good graces, it could even be that the Derek post with moose head was posted by Derek on it, good daddy Rusty is a laid back dude and could have given him the pass word, then Derek who cannot keep a secret tells Camilla due to being entranced by her arse.
It's hypothetical of course.
Or maybe a thoughtless Dik simply wrote down the password or left a device connected to it, Tweedledee(Jamie) and Tweedledum(Leon) are prime candidates for this act of idiocy.
As for hacked, with direct access and a device available to multiple individuals, any number of scenarios, including Nitwit(Jamie) and Numbskull(Leon) just leaving the pass word on a scrap of paper or even on the missing phone.
Whomever has the phone would suddenly have access to everything.