With cost savings as an issue, perhaps you could eliminate the schottky on the A/D input. Assume worst case capacitor voltage of 60V, the capacitor is viewed as a voltage source and the voltage source & resistors are transformed to a 6V source with 100k series impedance. Only 60uA would flow through the microcontroller's ESD schottky on the A/D pin. Latchup is caused by current in the order of hundreds of milliamps, right?

My $0.02 worth.

- Lee