In terms of 3., the English sentence is in the present tense (he fears) but the French one is in the near future (he is going to fear). I think what you mean is:
Il n'a plus peur.
Or if you want to say "He isn't going to fear homework any more":
Il ne va plus avoir peur.
If you say ''Il ne va plus avoir peur des devoirs'' you are actually saying ''He is not going to fear his homework'' But if you want to say ''any more'' it is enough to say ''Il n'a plus peur des devoirs'' So I agree with thedov.