Vietnam
Out of those letters, I'd try America.
England
Austria
America
One country that fits your criteria is Finland. It has seven letters, the third letter is 'n,' and the sixth letter is 'a.'
Harriet Tubbman
One Goddess with 7 letters in her name is Demeter, in Greek mythology. Also ARTEMIS.
Giraffe has seven letters
The actor and presenter you are referring to is "Matthew Fox." He has a first name with 7 letters and a surname with 3 letters.
A desert county with seven letters includes Algeria.
England and America to only name two. I would consider looking at a map or an atlas for future reference.