Ah! Gotcha!
Okay, so for the early characters (Damien, Jolie, and Cassandra), you'll want to chat with them at one of the locations you build (The gym, shakes 'n sundaes, or the computer cafe). Each of the starting characters does appear in two spots, and you'll have more options if you exhaust their conversation in both.
Once you've reached the point where you know what they want, head to R&D and talk to Mason. He'll have a lost of the focis you can make, which you then take back to them in the corresponding location
Let me know if that doesn't do the trick!