I bought my 2 speed Scott about 7 months ago. At first it had lots of niggling little problems, more than you have, but by tackling them one at a time it now runs nicely and the water does not boil, the 2 speed gear does not leave an oil slick and the kickstarter ratchet never slips.
Please take the time to find out just how the kick starter works, and exactly what is going on, rather than trying to fix it…. The ratchet should immediately drop into full engagement, not occasionally catch. Putting it up on the rear stand, resting the spark plugs on the engine to earth them and then operating the starter by hand should show exactly what is happening. The solution will then be apparent.
I have found that the 2 speed gear needs very little oil, gradully reduce the supply each time you go out. I drive at least 5 miles before operating the pump and switch the supply off before the end of the journey.
The water spray is probably due to a leak in the system, likely at a hose joint, first losing water followed by the boiling. Excess water should exit by the overflow, not from the radiator cap so the overflow pipe may be blocked…….