All sorts of things consume power--the displays, the shutter, the auto focus, the flash--how they divvy up on a particular camera is almost impossible to say. The CIPA score should be taken less as predictive than as a way to compare cameras. Your shooting habits and your menu settings can wring out a lot more frames than the factory settings. It seems likely an EVF consumes less power than the back display, but I wouldn't want to bet that's the case with every camera.
As to color, use an expanded color space and shoot RAW. Then you needn't be too concerned about color response across brands (Foveon sensors being a notable exception). I've never used a Sony camera so don't know what their jpegs look like before post processing. FWIW Sony produces chips for others, notably Nikon.