The first time you visit, ask everything. When you leave, Joey sticks his head back through the door, and you have two options: leave, or stay and eavesdrop. Yeah, let's do that thing.
Hint 2
Most of their conversation is fairly pointless -- Rosa does not either waddle like a duck! -- but you do find out that they use Bmail, the same email service Rosa uses.
Hint 3
Back in your apartment, look at Paul's business card to find out his login is PaulM. Now we just need his password.
Hint 4
Go back to the office, leave, and send Joey in to eavesdrop. Go stand over by Paul especially. Remember Joey's interference with airborne radio signals? We're going to use that to our advantage.
Hint 5
If you stand against the back wall, you'll interfere with their wifi set-up. Move to the right to let it come back, and when Paul signs on again, he'll ask Charles to remind him what is password is. Aha!
Hint 6
Back at the apartment, get on the computer, log off as Rosa, and log in as PaulM, password tennis53. (This won't work until you hear Charles say it, by the way.)
Hint 7
Unfortunately, there isn't much here that's too interesting. The only helpful things are a hint about how to talk to Claude --