With very few exceptions, you should be able to check anything. That should cover you on the ground.

Carry-on emergency gear is probably not needed. Unless you pack a parachute, I can't think of anything that could help an air disaster.

And if the plane DOES crash, emergency crews tend to show up to things like that within 5 minutes. Large passenger jets tend to attract a lot of attention when they make landings in places other than airports. Let the police and paramedics bring their emergency gear.