Whole house carbon filter installation with softener

We live in a lake community with our own water treatment and sewer system. The water is good, but very hard. No sediment, no iron or sulfur, but a chlorine smell and taste sometimes. I need to install a water softener, I know that, but the wife is insisting on a whole house carbon filter and a RO system under the sink.

The softener and RO I am pretty confident on hooking up, but my question is:
Does it matter where the whole house filter is installed in the water system? beofre the water heater? between the water heater and the softenr?

I am thinking the best place is between the main supply and the softener and water heater with a bypass of some kind. Where do most of you install this type of unit?

thanks

You want it before the water heater and after the softener.