A recommendation for a fast-response-time-resolution-mp3-module for arduino
I'm going to suggest that you stay away from these mp3 modules. It is perfectly reasonable to use a stand-alone arduino unit to directly generate sound using the digital output pins with a low-pass filter RC circuit. This is the most efficient way of doing this and will give you a very low activation latency.

https://playground.arduino.cc/Code/PwmFrequency/

The other option is to connect a DAC circuit and simply build a sample table for the wave outputs you need for each tone.