Answer:

anti: achiral, C2h	syn: achiral, C2v	gauche: chiral, C2 (object)	gauche: chiral, C2 (mirror image)
anticlinal: chiral, C2 (object)	anticlinal: chiral, C2 (mirror image)

The chiral ones should come as two enantiomeric forms, i.e. "doubly". Convince yourself that this is the case, see the torsion profile of n-butane in chapter 3D basics. What are you able to say about all other conformations of n-butane (we here neglect torsion about the external CC bonds)?