Wouldn't this be the same as using a single-throw double-pole (STDP) momentary-on push-button switch that could be mounted in the bumper? The momentary-on is required to prevent burning out the coils of the switch machine unless you are using a switch motor that denergizes the coils when it moves.
Depends on what you mean by "this". As I see it, the key component/function is the latching relay...or something equivalent that remembers which direction the switch should flip to next.
But if you're referring to previous comments about the reliability of the insulated-rail method with lightweight trolleys, then sure, you could use momentary push-buttons mounted in each of the bumpers (A, B, and C). The A and B push-buttons (or hand-built spring lever contacts) would momentarily trigger the set and reset coil inputs of the latching relay. The C push-button would momentarily supply power to the "COM" output of the latching relay which steers that power to one of the two turnout solenoid mechanisms.