Will this molding fit if my bumper cover has a sensor hole?

Sensor holes are cut into the bumper cover itself, not the trim molding. This piece mounts to the bumper structure independently, so sensor placement won't affect fitment. Test-fit to confirm alignment with your specific sensor configuration.

Do I need to paint this before installing it?

This molding ships unpainted. Paint matching is up to you—take a bumper sample to your local shop for a color match, or handle it yourself with automotive ABS-compatible primer and top coat.

What's the best way to secure it after removal of the old molding?

Factory attachment method is not specified in the product data. Before committing to adhesive or fasteners, test-fit the molding at the factory mounting points to understand how the original piece was retained, then proceed with the same method or a suitable equivalent.