Do I need to reuse my existing hub or wheel bearing?

This assembly comes with bearings and seals already installed, so you mount it straight to your axle housing. Your existing hub bolts to the spindle the same way OEM does.

What about brake components — do I need to transfer my calipers and rotors?

The knuckle itself does not include brake hardware. You'll transfer your existing calipers, rotors, and brake lines to the new assembly at the factory mounting points.

Is this a left or right assembly, and can I get the opposite side?

This is the rear right side only. If you need the rear left, order separately — confirm which side you're replacing before checkout.