MHSv1 Nano Biscotte V4 Assembly questions

This is my first build and have a couple of questions.

1. I bought the prewired MHSv1 Nano Biscotte V4 Assembly and from using manual and online info I have got this wired up and working on the bench for neopixal. But there is a JST connector wired to Channel 2 and 3 and I don't understand what this is to be used for, if not needed I would like to remove but don't want to remove if needed for something I am missing or don't understand.

2. I wired up things in stages and when connected the switch LED across the DS pad and - pad with a resistor on the DS line per manual so switch light goes out in deep sleep mode. This seems to cause the saber to keep cycling what I believe are clash sounds. this wan't happening with just the switch part and not the LED part of the switch.

Any help or advice would be much appreciated.