The first sentence requires ‘to’. The correct sentence is: The naming of cats, according to a famous poet, is a difficult matter: “It isn’t just one of your holiday games.”
The second sentence requires ‘with’. The correct sentence is: Most eminent politicians in India would agree with the seriousness of such matters — except that ‘cats’, in their case, would have to be substituted by public institutions, facilities and welfare schemes.
The third sentence requires ‘than’. The correct sentence is: Naming a new university, hospital, flyover or rural yojana is much more than what the usual business of civic commemoration might suggest in a modern democracy.