Answer's to all your questions:
http://www.byaroch.com/Cougar_LED/Cougar_LED.htmYou can buy the 3mm leds at Radio Shack ($3 each) but they have to order them. There was a link to a site that had them for $.50 but he sold out and will supposedly get more "towards the end of January" (Now, I hope). I'm waiting for his site to restock, and then ordering a bunch.
You would need 7 for window switches, and 2 for unlock, so 9 total.