Firelink Shrine is a much smaller area than the Nexus. You'll only ever have like 5 NPCs there at the most. The NPCs will travel around Lordran on there own. There are triggers of course that make them move around which can be avoided if you know them.
Generally, the three beginner spell teachers will hang out in the Shrine, though two of them will leave down the road if certain triggers are met. Other NPCs will come and go at various times. --- ~El Psy Congroo~ PSN ID: FatBeezzee