Contacts depend on your character's details. If he's undercover as some upper class socialite or security specialist, doing high-risk jobs (international or local) for different people in between enjoying his life he'll have probably a number of contacts related to that - a hacker, a smuggler to get to places and to get supplies, maybe another fixer, maybe information networks. If he is connected to a criminal syndicate instead of being a lone wolf he might have more ties to the gang or syndicate.
If he's a more middle-or lower class type, doing local jobs that run the gamut from legal to illegal, he might have more a private detective's contact network - snitches, gangs, cops, a fixer.
For background meshing I'd have to know more about him, both professional and private aspects. Was he sent to infiltrate some organisation, or to hide from someone? Is he trying to build a powerbase to take revenge on someone, or doe she have some private pursuits that he finances?
I am pretty open with regards to possible ties. Keiko could know him professionally and/or privately. I picked a Triad as the syndicate she owes money to, but that can be changed to any other syndicate to forge some links between characters, in case anyone else has ties to organized crime or a larger gang, or to a nightclub/stripclub she works at (dayjob). I have also not yet finalized what kind of hold the syndicate has on Keiko - could be a ritual sample stored somewhere, or some kink bomb implant, or some personafix implant (like "follow X's orders"), or psychological (feeling beholden/obligated for help received, or simply intimidated etc.).
Another PC could be a roommate, co-worker or even her boss or handler, or someone she met on the trip to Seattle. Could also be someone who bought her "contract" from the syndicate.
Keiko's new in Seattle, somewhat recently arrived, so she'd not have known anyone for long.