Ok, so this is how your charecters are going to have a twitter.
All you need to do is make a post like this.
@TwitterUsername:
Bio:
That's it! Way easier then actual twitter.
Then to tweet then do this.
@TwitterUsername: I'm SO BORED! #SoBored
Then another character can reply on the thread like this.
@AnotherTwitterUsername: Come on join me in the lounge!
That's how it works.