This song was played by many live-performed instruments and acoustically, the songs sounds like a real recording of a big band concert, at least that was the goal of it.

The song contains the following instruments:

Drum Set
Baritone Saxophone
3 Alto Saxophones
Tenor Saxophone
Tenor Trombone
Trumpet
Trumpet with harmonic cup
Contrabass
1st Violin
String section (Violins, Violas, Cellos)
Organ
Xylophone
Glockenspiel
Flutes
Oboes
Grand Piano
Theremin

I would be pleased about feedback!