nothing but positives... Small but postives. I am very pleased with you calling as you said you would and I am pleased that he called back as he said he would.
He opened up and shared stuff with you for sure. 30 minutes on the phone sounds like someone was trying to make contact with a dear... friend? Hopefully. Sending the song to me sounded intimate.
Next time will be easier for you and you will be able to shine even more. I would definitely try to keep in touch in a way where he doesn't need to respond. Like " this is song I like, I hope you like it too", did you notice? No question.
Then something else, something else, THEN a question, then a call, build up communication patterns...
