Since holograms that are animated and aren’t viewed through a photographic plate are still the stuff of science fiction there is no ‘canonical’ way they should look. It’s pseudo-science so you are free to make it look however you like, ie. there’s no ‘wrong’ way to do it.
A hologram is an effect of light and has no solidity (OK, Star Trek ones do but whatever) so the holographic object and any projection cone you include probably shouldn’t receive or cast shadows. Also, I’m not sure whether it’s possible in Anim8or but ideally they shouldn’t be affected by lights in the scene other than one positioned near the projector illuminating the holographic object directly.
Including a greyscale white-to-black gradient image mapped in the transparency field in the ‘projection cone’ object will make it appear to fade away at the top.
This quick test incorporates Kevin Gales’ concept and johnar’s flickering idea. There is a green light illuminating the hologram from below, perhaps a script in the light colour/brightness channel that incorporates randomisation would look interesting, adding a bit of flicker. I have minimised the effect of scene lights by reducing the specular amount in the textures used for the holographic elements to zero and increased the emissive value to about 0.5 with a green colour to make the holographic elements appear to glow. I haven’t done it but including a soft green ‘bulb’ light in the centre of the holographic object that casts a bit of a green glow on surrounding objects would be a nice touch too.