are omega and n both unit vectors?

Yes. as they all have the same length, from the Parallelogram Law of vector addition, we have $\omega_o + \omega_i = 2 \cos(\theta) n$

are omega and n both unit vectors?

Yes. as they all have the same length, from the Parallelogram Law of vector addition, we have $\omega_o + \omega_i = 2 \cos(\theta) n$