Q. Which bike is better R15 V3 or FZ-S Fi V3 for a 5.6 height person?

I rode both vehicles. So in my opinion the R15 V3 is very powerful but your posture would be very committed (you would be bending while riding) due to which you would tend to have a back pain. But if you are used to riding sports bikes then this might not be an issue at all. On the other hand, the Yamaha FZ has an upright posture due to which it's more like sitting on a comfy chair and riding. I would suggest you to ride both and then decide.

Go for R15v3

You can look for the gixxer sf 155