3.5 headphone and 1/4 cable, and MIDI output with Arduino powered instrument

Hey, so I'm pretty new to Arduino, and this is my second forum post.
A long time ago I was shown a YouTube video of this guy who had made a "laser harp" where if you broke the stream of a laser with your hand, it would register that and make a sound. I want to supersize this project, making essentially a table (imagine a hollow coffee table with lasers running through it) of 64 lasers and sensors. (It came to that happy number because, since I am a pianist, I decided to make the "strings" 3/4 inch apart, and the table 4' long)
I didn't know exactly where to post this, so I decided to break it up into a few different topics, this being my second post. (First one was in multiplexing about using 64 LED inputs)
I wanted to know how to output sounds, sound files, etc. hopefully simultaneously to the 3.5mm traditional headphone-style jack, the 1/4 inch guitar style patch, and output as a MIDI controller like a piano would, based on sensor values.
James D.