Here is the frame that seems to capture the gist of this show's appeal for me. I hope it helps.
Each show is a jazz piece, stand alone, played by instruments.
The instruments are the characters, and we start with just Jet, and he quickly pairs with Spike, and a simple duet is formed, rhythm and bass so to speak. Faye, Edward and Ein all join in on subsequent episodes, and we have a quintet.
Each character, after they are introduced, plays along in combo with the whole, but then each gets a "solo", a show about mainly them and their back story. In Edward's case, her solo also forms her play off.
After the solos, each member drops out, and we are left with Spike and Jet, and then finally just Spike.
Fin.