This is my first attempt at writing for flute choir, and it’s an interesting process: For one, alto flute is essentially the only instrument I can think of that transposes in G. Moreover, the actual range of the ensemble is really skewed high! A bass flute’s lowest note is C3, an octave below middle C. That’s hardly a “bass” instrument by my reckoning but because you have such a huge spread upwards you still have a lot of range to work with!
I suspect the first playthrough of this will reveal many beginner mistakes in writing for this wonderful ensemble, especially for those lower-ranged flutes. Either way, I think this was a fun first foray!