UnScramble this Word: o a e t t p?

Questions

what english word comes from the old french covrefeu meaning 'cover fire'?

which member of the peanuts gang once said 'there's no heavier burden than a great potential'?

what comic was korky the cat in?

what is the nationality of agatha christie's detective hercule poirot?

what is the shortest word in english that contains the letters a, b, c, d, e and f?