If your intention is still use the Maestro Fan Control/Dimmer setup? The same problem will exist for any secondary controller you may want to use. The Maestro wall switch is basically a wireless remote controller that does not use batteries but 120v hardwired at the switch gangbox. It communicates wireless back to the receiver in the fan cowl. I don’t know of any way to install anything in conjunction with that kind of setup and not cause a conflict. For example putting the Aeon micro dimmer could possibly work for dimming the light only but your wall switch has no way to know that is what is happening so the indicators would be off sync.
I am like you in that the Maestro Fan Dimmer control is the perfect solution look, function, indicators for the user and deeply hoped that Lutron would make a z-wave version of the receiver for it or in the Caseta lineup at least. Just been waiting too long and this Hampton Bay receiver is the best fit thus far for SmartThings.
If you like having the wall switch look this is the closest I think we will get… there is a slight possibility that this MIGHT be compatible with the zigbee Wink receiver with the custom device handler but no one has reported testing it yet.
FYI:
I am modifying my smartapp for 3-speed fan control to be compatible with this new device but if you want temperature control from a local table top remote this Hampton Bay
Universal Ceiling Fan Thermostatic Remote also has a chance to be compatible with the zigbee receiver.