With hypochlorite (ClO-0-) doesn't really have a central atom as there are only 2 atoms present.
As for your other answers :
H3O+: H Incorrect
SbF4−: Sb Correct
XeF2: Xe Correct
COF-2- ?
SO32-: O Incorrect
Generally, the atom with the higher valency will form the centre of the molecule.