No problem at all.
Tip: Always use Fully Synthetic engine oil in your car/motorcycle.
Nothing happens, they just mix. You can buy "blended" motor oil.
not much. it would change the viscosity of the oil. the diesel oil is much thicker than regular engine oil.
Nothing terrible will happen but the old oil in the filter will mix with the new. I would recommend you change the oil and oil filter again. This will insure that you will have clean oil throughout the motor.
Yes, you can mix conventional oil with synthetic oil with no problem.
Yes
If you put in to much oil it will smoke really bad, or will not run. If not enough oil you will damage motor.
what happens
It is a gas/oil mix motor, you don't change the oil.
As long as the light remains in the motor oil, nothing happens to its speed.
Motor oil is insoluble in water and it is denser in water. Therefore, motor oil will not mix with water. It will remain separate.
Yes, and you can even mix them together.
It will probably just foul the plug or wreck the engine because the oil is not designed to mix with the fuel and will not lubricate the motor.