While I wait for my DFRobot boards to arrive from China I'm going to work on the menu first.
I have a few Arduino Nano boards kicking around; it's breadboard-friendly pin layout is perfect for prototyping. I also have an lcd display and a rotary encoder already, so I can attach those to the breadboard with some male-female jumper cables.
This little setup will enable me to work on the menu and selecting/setting the parameters, and also committing the parameters to EEPROM so they can be loaded on startup.
I have also ordered a little DFRobot mp3 module for this setup, which, when it arrives, will allow me to test reading data and playing sound from it's onboard Micro SD Card slot.