Stuff used:
Qsynth (GeneralUser GS 1.4) for Flute and Piccolo
Hydrogen (Millo-Drums_V.1) for percussion - except tambourine shake
ZynAddSubFX for everything else
Rosegarden to tie it all together
The percussion track was quantised, but everything else is free-flowing.
You have ended up with something akin to a complete orchestra, here Will, and very nicely deployed