Well, first of all you said you want to do the sound mod, so you should either be using the LM362 or wiring them up straight to the speakers. They are shutting off probably because you are going straight to a 5v point with no resistors. I think that blue LEDs have an intake of 3.6v so they are perfect for the speakers, but if you use any other color you will need to use resistors. as for wire, try 30awg wire from radioshack.
And i dont really under stand the 15-16 LED part, but if you mean your gonna try to stuff them all in to the psp, you just solder them the positive side to positive speaker terminal, and negative side to negative speaker terminal. your gonna have a serious wiring issue though.
And for the button degree angle, any angle should work, I think you should just put one in the middle of the X O [] /\ buttons, or else you may mess up the contacts.
And for the chotto cam part, try the Auctions section.