How are these instruments for composing a movie score?
 

I want to give a shot at composing a score for a low budget indie movie, and I will be using samples of the instruments probably, if I cannot find real players, but what do you think of my choices of instruments? Do I have enough or should I use more?

Violin, Cello, electric and acoustic
Synthesizer
Trumpet
Bass Trombone
Tuba
French Horn
Taiko
Timpani
Snare
Bass Flute or Pan Flute
Acoustic Piano
Electric Guitar
Harmonica
Bell
maybe Xylophone
maybe Classical Guitar
maybe Duduk

Needs cow bell.