Not sure what the issue might be. You avoid using the eDRUMin MIDI Monitor. There's an issue right now where if more than 7 messages arrive within about 50 ms, it will likely crash the eDRUMin hardware. But as long as the MIDI monitor isn't open, there should be no issue.

Do you happen to know what firmware version you are using?

You have the pot wired up as a rheostat and have it connected to the bow piezo of the cymbal?

It's definitely designed to work that way. Does the DM8 power itself via USB or does it have an external power adapter?

There is no single standard of converting MIDI note numbers to MIDI note names. Some applications set C4=60, some set C3=60, and I'm sure there are even more standards. To avoid any confusion, you can enter note numbers into the eDRUMin custom notes, and that'll work as expected. Also, although not ...

Hmmm. There should be a 'load' icon which is an arrow pointing up.

To be honest, it just sounds like you don't have your decay control set optimally.

I can't recommend a sensor, but I can confirm that you indeed wouldn't need any resistors or pots.

I just got my Midi Expression interface to use it with the TC Switch 3. I upgraded to the latest 2.9.3.10 firmware and tried it out. Unfortunately it seems not to work for me - if I select the 3 button footswitch, the press of the 3rd switch is registered as presses switch 1 & 2 together... Can...

*should*, but I've never tested them myself.