Yes, a 720 will fit.
AND.. mostly yes on the electronics.
You will need the cdi/coil for the 720 engine, (change #1) and you can tie the kill into the rev limiter of the 92's electronics.
For change #2... the rev limiter of the '92 is 6500 rpm. The 720 engine's red line is 7000 RPM. SO... unless you install a new rev-limiter... you really won't gain anything by putting in the bigger engine.