I am building a museum installation that will have 28 sounds that can be played individually or polyphonically from individual buttons on the instrument’s surface as well a 1 button that will stop all sounds playing. I thought using the qwiic Tsunami and an Arduino mega joined together through midi-usb. I don’t need to do anything other than start the individual sounds and stop everything which is why I opted for the Mega since it has so many digital inputs. I thought resetting would accomplish the Stop function. Is this a good idea? Thanks in advance.
Yep, that’d work great - just note the Tsunami can do either 32 mono or 18 stereo tracks, so you’d likely need to wire 2 of them to the Mega if using 28 stereo sounds, or just one if mono 
How about using a wav trigger with the mega?I don’t need all the sounds to play at once.