the Kawi is simple. It's a 2 wire start makes the starter spin and a 2 wire stop kills the spark. Any 2 wire button setup can be used. There's individual aftermarket buttons you can use as starts, and lanyards you can use as stops. I'm not familiar with any aftermarket stop/lanyard combos, but you might be able to splice some wires to do it.
Not all switches are made the same. The XI switches will work but incorporate an electronics trim so they are very large. The SJ switch could probably work but would need some wiring. The Superjet switch works differently than the old kawi switches. The Kawi switch is 2 seperate relays, but the Yamaha stop is tied to the start. On the kawi, if the lanyard is off the starter still spinds but no spark. On the Yamaha, if the lanyard is off, then the start button wont work. Slightly different wiring.
Anything can be made to work. The only thing that will be plug and play is the part that was made for it. Otherwise, plan to splice some wires together.