What, you think it's physically impossible that someone could reuse a password on more than one service, or register them all with a single Gmail account?
No, it's just incredibly unlikely that someone hijacked four different services and have been able to keep the owners locked out of their accounts.
You only have to hijack one account if the password across all four services isn't unique.
Yes, but the owners have four different support lines to call to get their account back, so the odds of it staying compromised is that much lower.
How do you explain that nobody working there is talking about being hacked? Do you think everybody there was using the same password for their Twitter accounts, Facebook, etc...
Or just automate the reproduction across multiple outlets. I use a FB app that posts tweets to my timeline for example.