Do these require any wiring work or do they plug straight in?

Wiring configuration is not specified — test-fit the connector at your marker location before assuming a direct plug match. You may need an adapter harness depending on your vehicle's factory connector type.

Are the bulbs replaceable if one burns out down the road?

The bulbs come pre-installed, but replacement accessibility depends on the housing design. Check if the lens pops off or if you need to remove the entire assembly to swap a bulb — this detail isn't confirmed in the specs.

Will these fit if I have an aftermarket bumper or splitter installed?

Stock mounting points are designed for factory bumper geometry. If you're running a modified front end, measure clearance between your bumper and the marker housing before committing — fitment can shift with body kit changes.