lipo will work with any brushed motor and speedo
electrial donts
dont connect red to black and black to bang
use a lipo charger for lipo, dont discharge them below 6 volts and use a voltage cut off, charge them at 1 c ( 5000mah pack would be 5 amps, 4000 = 4 amps)
2.4 some say not as fast but alot less chance of clashes or interferance
not sure on your other questions