The colors something normally has don't influence a heat signature at all. xD It's exactly as the name suggests; heat influences what colors are where. And generally, a living being would be largely warm colors, especially in its middle, where heat is most concentrated. Limbs would be lighter colors, like perhaps orange or yellow.
And I have no idea how it would work on the Ebilia or Jaaku. It seems like it probably wouldn't work at all for an Ebilia, as they probably don't retain or generate any heat, and a Jaaku could only work if you applied the whole, 'Ghosts draw energy from their surroundings to manifest themselves,' thing. Even then, they'd have a lot more yellow and green than the rest of the pets, so they wouldn't really seem to fit.