Do these plug into factory fog light wiring, or do I need to run new harness?

This kit comes with a switch and harness — you're not tapping into factory wiring. Run the included harness to your battery and ground point, then mount the switch in the cabin. Mounting method not specified, so test-fit before committing to adhesive or fasteners.

Will these work if my bumper doesn't have pre-drilled fog holes?

These are designed for factory mounting points. If your bumper opening doesn't exist, you'll need to cut or modify the bezel area — that's a fabrication job outside this kit.

Does the smoke finish need to be sealed or painted before installation?

The smoke lens is a finished part ready to install. No prep work required. If you want to adjust the finish or protect it further, that's your call — but it ships ready to bolt on.