Electrics can be confusing. To be honest, I'm still confused with some parts, like the motor sizes. I don't know if that 380 number translates into a certain dimension. I think it does, but dont quote me on it. As for the esc, the 20 amps is the maximum current that the esc can handle. If your motor tries to pull too much, your esc could fry. If you have a multimeter, you could hook it up in series with the motor and see how much your motor is pulling. 20 amps should be plenty for most planes. I have an 18 and don't even worry about overamperage.

Your package should be fine for most aircraft the size of the sky pilot. You will eventually want to get a brushless motor and lipo pack, but you don't need to now. It took me 4 years to finally upgrade my stuff.