I have the EasyTouch4 and I was going to recommend the 8. Better to have too many relays than not enough.
I only have a simple 120 volt standard white light, so am not using any lighting programs except on/off. But.. I can't see where it says that 12 Volt lights can't be used. Where did you find that statement in the manual? It may be a fact, but just does not sound right. It appears to me that external lights can only be controlled by one or more of the control Aux relays. If this is true, than any voltage you want can be used.
The real challenge will be programming the EasyTouch to do what you want. It is not user friendly, not hard, just not as intuitive, as I would have liked.
Jim R.