A few thoughts:
1. Why do you need a pact with the devil to chase out the French? Couldn't the Haitians have sent a telegram to the French telling them they would fight back? The French would have run away.
2. Why would God or the Devil, whomever sent the quake, wait generations to punish the Haitians?
3. Isn't it at all possible that the science of plate tectonics is not influenced by the devil? And that unlike a place like California, Haiti has such poor quality construction that an earthquake completely devastated the country?