So cute, how do u know he doesnt mind u listening to trance music?

If you want to see him active, try doing it at night. Switch off the light and wait until he realized that his surroundings is dark, then he'll come out and start exploring. That's what I always do with Pickle, he would run out from his hidebox and explore, and start running inside his wheel, and when you put your hand inside, he'll climb to your hand, asking you to take him out to play.

Ren is cute la, everytime see him sit on his butt butt only... hahahahaha

2-3 pellets per day? How long he's been eating so little?

You changed his diet or made any changes to his cage?

Ahhh... the journey from pg to kl is the reason. Your hedgie is stress, don't worry, pay more attention and don't disturb him too much, he'll be fine in days