1) yes, it still draws a current, not much but it is always better to use s switch or a connector.
2) it depends th quality of the plugs and solder but I think up to 5-6 amps should not be a problem.
3) a 2300 with a high C-rate (at least 30C) should not be a problem to use it for a weekend. With the low price of some Higher capacity LiPo (hobbyking) it is better to get larger ones.
Speed is only fiction but a 130+km/h MRS4 is for real.