control and char(muxarray) - to the serial port.
We have been through this once. The middle parameter is the CC number you want to change.
Yes you could write like you said at the end but then it would not be a useful function. That function will send any three byte MIDI message if you pass it the correct parameters.
Try changing that function to:-
void MidiTX(byte message, byte control, byte value) //pass values out through standard Midi Command
{
Serial.write(message);
Serial.write(control);
Serial.write(value);
}
That is change the data type to byte and don't use capital letters, they are reserved for constants - not required but a style thing.