Do I need new brake rotors or pads when I install these hubs?

Not necessarily. Hubs and brakes are separate systems. Inspect your rotors and pads during install—if they're worn, replace them then. Many people do both while they're in there since you're already at the wheel.

Will these work with aftermarket wheels and spacers?

Yes. These mount at factory rocker points and accept standard wheel lug patterns. If you're running spacers, verify your bolt length doesn't bottleneck the hub seating—spacers shift the wheel face out, but the hub mounting itself doesn't change.

What tools do I need to swap these out?

Jack, jack stands, socket set, and a hub puller or bearing separator if you're not replacing the entire assembly (which these are). A torque wrench is recommended for final assembly. Refer to your service manual for torque specs on the axle nut and mounting bolts.