I've replaced that hi/lo part a couple of times with the genuine kit 99990-530. It's $100 a piece from Canada to Australia bought from Vintage Kawasaki. I'd be happy to pay $42 if the part lasted longer than the OEM piece.
As for switch interchangeability, I can say the headlight "on.po.off" switch in the replica will not fit an OEM right switch block but a replica lower half can be used with an oem upper half. That is how I overcame the issue with not having a headlight on/off switch.
Maybe the hi/lo from a replica will interchange into an OEM. I've been considering a replica left switch block from s/kh series for the the choke control of the HSR42 carb on my turbo. It's $80 in our money but probably worth it if the switches swap.