People drive in gravel and on dirt roads all the time. Unless you heard a big rock hit the underside of your car you are fine.

Good support and communication.

Depends on the car but keep all of the fluids changed, tires rotated, and tire pressure checked often. Keep the air filter and cabin filter changed every 15k or 1 year.

Perfectly normal. Clean it with a hub cleaning tool and put some grease on it to prevent it.