Reverse Polarity Protection, External Circuit
You are suffering from the paralysis of analysis. You simply cannot account for every possible bad scenario. In fact you have done the most basic step already. There are a hand-full that work well with very few parts.

A series diode. Yes, a Schottky diode would cause less voltage drop, and I am not sure why you have a diode on the ground side. D1 and D3 protect against reverse hook-up of the sensor, so D2 and D4 are redundant.

The only additional protection that actually works is a series resistor of 1 K or so before D1 and D3, and a 5.0 to 5.1 volt 1 watt Zener diode to ground after D1 and D3. Now you have over-voltage and transient protection as well.

U1 likely has high-impedance digital inputs so a 1 K resistor is more of a transient current limiter. If the inputs seem sensitive to noise add a 10 K resistor from the input pin to ground, and a 1 nF capacitor across those resistors. Now it is much more immune to local EMI noise such as hand drills, CCFL or florescent tube lighting, etc.

Per @mkeith's comment below, make sure you use polarized connectors.