The difference, as far as motor protection is concerned is nothing. This is because a reversing starter is nothing more than two contactors instead of one for the non-reversing.
A reversing starter uses one contactor for forward (pass through) and the second to swap phases for reversal when energized.
In both cases, the motor protection is "after" the contactors.
Not sure EXACTLY how a solid state overload functions. A eutectic alloy overload relay heats up from motor current and releases a mechanism to drop out the motor.
To visualize this, imagine that a shaft is held in a pot of solidified solder. The motor overcurrent heats the solder around the shaft and frees it. When the shaft is free to move, it opens a switch, dropping out the starter coil. This is how eutectic alloy overloads work.