If you use the 6 button keypad you can have the large top & bottom buttons work as ON and OFF for the main light and the other buttons for the fan and anything else you like. They offer an engraving option for the switch labels. They used to have clear caps too so you could make your own labels. The keypads contain one dimmer switch so noting else is needed in the single gang box. The inline module for the fan can be installed in the fan housing.
As for what to do with the extra buttons, here's an idea: Assuming the inline module for the fan is set to A2, One button on the keypad will be set to A2 for simple on/off. Use the other 3 buttons as timers for the fan, say, 10, 20 & 30 minutes. When you press the 10 minute button it could transmit A3 ON. When your controller sees A3 ON use it as a trigger to send A2 ON, delay 10 min and send A2 OFF. A4 and A5 would trigger the same response with different delay times. Now the extra buttons will make sense if labeled "FAN 10" etc.
Another option is to use the top large button to toggle the light and the bottom large button to toggle the fan and the other for as timer buttons.