My suggestions (I've made some moderations based on Mariemaleche's):
4 Quel est l'animal dont tu as le plus peur?
Which animal are you most afraid of?
5 C'est un pays dont j'aime la culture.
It's a country of which the culture/whose culture I like
6 Ils ont 3 enfants dont deux vivent à l'étranger.
They have 3 children, two of whom live abroad
7 La maladie dont elle souffre est très rare.
The illness which she is suffering from is very rare.
9 C'est un homme dont on ne sait rien.
It's a man of/about whom we know nothing.