For reverse leds, if your brushed, hook the positive led to the negative on the motor, and negative led to positive motor. Use a quality wire with proper gauge, and the led will light up in reverse.
I havemt tried brushless yet, but am planning to this weekend.
For brake lights, I use the...
Look at hey ok rc. They have the brake light circuit and the on off toggle via 3rd channel. Looking at new items is rock lights also.
https://www.heyokperformance.com