Do these bolt straight into the factory holes?

Yes. These mount at the factory rocker points with no drilling required. Test-fit before final tightening to confirm alignment.

Are the bulbs included, or do I buy them separately?

H10 bulbs are included. Just unbox, mount, and wire them into your harness.

Will I need an adapter or relay harness to wire these in?

Wiring depends on your vehicle's existing fog light circuit. If your truck was originally equipped with fogs, the harness may already be there. If not, you'll need to source or fabricate a relay setup — contact a local shop or forum community for your specific year and configuration.