I would say that 'more than one' requires a singular noun so the third sentence is incorrect (in my view).
In the first sentence 'more than one subject' is the subject of the sentence (in singular) so it should be correct.
With regard to the second sentence ,it is possible that the noun phrase 'more than one subject' be regarded as a plural entity so I cannot rule it out as incorrect.
Words such as none, any, all, most , more can take either singular or plural verbs depending on the context.