I and S = good guess. We'll very soon have all the letters and no attempt at the title!
Code:
Category: Song Title
Letters remaining: * b c * * f g * * j k * m * o p q * * * u v w * y z
S i x t e e n L i t t l e R e d N - s e s
a n d a H - r s e T h a t S - e a t s