If you're looking for a laser that will show up on a IR Camera, you'll want to use good old fashioned red. Its the closest to the IR bandwidth so you stand the best chance of it showing up on an IR camera.
Green is pretty far from the IR spectrum, and you're right it doesn't show up very well. Blue/Violet is even farther so would be worse. Although the UV/Blue has a way of fluorescing biological matter, its really kind of cool! Not very paranormally relevant, but hey sometimes you just gotta go for the "Cool" factor...