Will this work with an aftermarket bumper cover?

Yes. This reinforcement bar is a structural component that sits behind the bumper cover and bolster. It doesn't interfere with aftermarket bumper fitment as long as the cover is designed for your model year.

Do I need to remove the front bumper to install this?

Depends on your comfort level with access. Most installers remove the bumper cover for easier bolt clearance, but the bar itself mounts at factory points without touching the cover. A lift and some patience with a wrench works either way.

Can this be painted before installation?

Paint it before or after install—your call. If you're matching body color, paint after mounting to avoid chipping during handling and bolt-up. If leaving it raw or primer, prepping and coating before install is cleaner work.