I will post the list here myself.
*sigh*... Here we go.
The green path in the hub should lead to Matthew Patel's level. It should be the second easiest level, and play Predestined Fate.
The yellow path should lead to Lucas Lee's level. It should be the third easiest level, and play Pushing Onwards.
The purple path should lead to Todd Ingram's level. It should be the fourth easiest level, and play Paced Energy.
The pink path should lead to Roxy Richter's level. It should be the fourth hardest level, and play Potential For Anything.
The blue path should lead to The Katayanagi Twins' level. It should be the third hardest level, and play Pressure Cooker.
The red path should lead to Gideon's level. It should be the second hardest level, and play Piercing The Sky.
As for the two multicolored paths:
The green and pink path should lead to the Starting Zone: You don't battle an Ex at the end, it should be the easiest level, and should play Passion For Exploring, and you start off here.
The yellow and purple path should lead to the Final Zone: You battle all the Exes at the end, it should be the hardest level, and play all of the music tracks.