Do these use the factory headlight connectors?

Yes. These plug into your stock wiring harness without adapters or splicing. If your Focus originally used halogen bulbs, the electrical connections are the same.

Will these work with my factory auto-leveling system?

They mount at the factory points and accept standard connectors. If your vehicle has factory leveling sensors, mount the housings at the same height as the originals to avoid beam aiming issues.

What comes in the box besides the headlights?

You get the driver and passenger assemblies. Installation fasteners and wiring connectors are factory-standard. Any trim clips or gasket seals not listed above are not included—check your current headlight assembly before removal to see what you're reusing.