There are plenty of low bias OP-amps. It still needs a clean layout and board to avoid extra leakage, especially when the humidity goes up.
For protection a high value (e.g. 470 K - 5 M) series resistor can do most of the protection. Most OP-amps have some internal diodes that are than sufficient. If needed bootstrapped low leakge diodes like BAV199 could be used as additional clamps.