I had problems with polyphony when using the serial input on the Arduino. I found others who had the same trouble so I'm not COMPLETELY crazy, but it's likely I was doing something wrong.
I didn't have that problem when I busted up a MIDI interface,made my own optoisolator circuit and sent that to one of the digital in pins.
Does this bridge get around the one-thing-at-a-time problem?
Hairless MIDI<->Serial Bridge
Linear Mode
