Are motorcycle foot pegs universal?

No, motorcycle foot pegs are not universal. Different motorcycles have different size mounts for their foot pegs, so you need to have a foot peg that list fitment for your motorcycle. Even if the width of the foot peg fits, the angle of the foot peg needs to be correct so the peg sits level.

Can motorcycle foot peg brackets be added to my bike for a a passenger?

Yes. You can mount a set of foot peg brackets to your frame so you can mount passenger foot pegs to your bike. The mount is called a foot peg clevis. You can purchase these in a simple bolt-on version which will enable you to just drill a hole in your frame where you want to mount your passenger pegs. Simply bolt on the clevis and then install your foot pegs.

What's the difference between rider and passenger foot pegs? Are they the same?

Rider foot pegs and passenger foot pegs are usually the same. The mounts or foot peg mounting clevis is usually different. This is due to the difference in mounting locations. The passenger peg mounting location is usually designed to keep the passenger’s feet up and away from the exhaust. The rider foot peg position is designed to accommodate all of the rider controls. Depending on the motorcycle, these positions might be extended to accommodate taller riders. This is where forward controls are often used.