The problem with the code you posted is that it isn't a program, it is a series of unconnected fragments of C. Even if I could make it compile (which is doubtful) it wouldn't do anything useful. The arduino environment is specifically aimed at new programmers so if you want to do this there is no reason you can't learn if you are willing to invest the time to learn. In this case I think you have the midi code that you tried to modify in working form somewhere earlier to get the buttons to or from midi, if you start with that and add the code to light a single led with the shift register even if it only lights the led when the button is pushed and it then stays on for ever, you should form there be able to figure out how the code works and how to change it to do what you want. I haven't actually looked at the arduino starting stuff because I already knew how to program micros in assembler or C but it is aimed at makers and artists who have never programmed before and thus must be able to teach someone inexperienced how. I isn't easy though, no type of programming is.
Peter