The second one will definitely work. For it to light up, you have to supply it with 3 volts of power. The first one may work but I couldn't tell if it was momentary contact or not.
IF the voltage requirement for the two lights is the same, I'd say, yes that you could do that. The other option is to simply use an LM317 linear regulator from Radio Shack and supply your own power. It'll cost you a total of about $6 bucks for the regulator and the resistors.
I was wrong; doesn't look like Off/On button is illuminated. I also see that there is only two wire attached at the back of the button. So, am I in trouble if I wanna use an illuminated one? I'm not using p1900/p5v as the Mini in my kitchen, in stead of car. Cheers!!!