I realy don't think the poly count is to high for the A6 & A7 engine I have run
models with a much higher poly count and had no impact on the engines frame rate when the full zombie models are finnished I would estimate the the triangle count to be around 5000 and from what I have read that is a good count for todays engine,The way I work is to make a good head and try to save the poly count on the body. That way you can still have good looking models without any impact on the framerate