Yep, those are the midi jacks - as far as I read, this was EES's generic oem style product and ended up in a number of synth's and organs, with a bit of custom code where needed.
I think the twisted pair is (mostly) for cancellation of Common Mode interference picked up by the cable, otherwise, don't you need a properly terminated shield to block emission from the wires? EMI is tricky as you have to have your shields and drains connected to ensure effectiveness....sometimes at one end only, other times at both etc. All depends on the related bits being interconnected...