Do these come with bulbs, or do I need to source those separately?

Bulbs are not confirmed as included. Check your service manual for the correct bulb type and grab them before install so you're ready to go.

Will these bolt straight into the factory bumper openings?

These are designed for OEM fitment, but test-fit before final commitment. Your bumper condition and any modifications may affect alignment.

What kind of prep do these need before installation?

They ship ready to install — no painting or finishing required. Just clean the mounting surface and you're good to bolt them in.