Do these need bulbs, or do they come with them?

Bulbs are not included. You'll need to source the correct bulb type separately — check your original equipment spec or your vehicle's manual for the exact bulb designation.

Will these work on vehicles that came with HID or xenon factory headlights?

No, these are designed for factory halogen models only. Fitting them to an HID-equipped vehicle will cause fitment issues and improper beam alignment.

Do I need to reprogram anything or adjust alignment after install?

Installation is bolt-in at the factory mounting points — no reprogramming required. You should perform a headlight aim check after install to ensure proper beam height and direction.