Are the below mentioned sentences correct? Please advise

English as a Second Language English Vocabulary, Grammar and Idioms
1
  1. That country is the leading of example of a well culturally integrated/assimilated country.
  2. That country is an example of a successful culturally integrated country.
  3. The country is the best in term of cultural integration.
  4. That country has a successful cultural assimilation/assimilation.
  5. That country is a successful culturally integrated/assimilated country.

Are the above mentioned sentences correct? Please advise.

2
  1. That country is a/the leading example of a well culturally integrated/assimilated country.
    ‘the’ indicates it is the only country which provides such a clear example, therefore logically ‘a’ would be a better option - it is among those few countries which offer such an example.
  2. That country is an example of a successful culturally integrated country.
  3. The country is the best in term of cultural integration.
  4. That country has successful cultural assimilation/assimilation.
  5. That country is a successful culturally integrated/assimilated country.