1) any standard, long, medium heat, plug will work.

2) the battery is considered dead when it reaches the stated voltage, in your case 4.8 volts, never go lower than 4.6V

3) As with any trainer this is a high lift flat bottom wing, meaning they are not meant for high G high speed aerobatics, it can take allot but high speed high g-s are going to fold the wing on any trainer.

4) I don't know much about the 2.4ghz stuff