Initial state selected time-dependent wave packet and quasi-classical trajectory methods are employed to study the effects of reactant rotational excitations and isotopic substitutions on the title reaction. The coupled channel (CC) and/or centrifugal sudden (CS) integral cross sections are calculated quantum mechanically. It was found that the CS cross sections are slightly smaller than the CC counterparts over the collision energy range studied. The quantum dynamical and quasi-classical trajectory results agree reasonably well and both indicate that the rotational excitation of H-2 enhances the reaction in all energies, whereas the rotational excitation of OH+ promotes the reaction more strongly at low collision energies but has a negligible effect at high collision energies. In addition, there exist significant isotopic substitution effects: The reaction cross section of the D-2 + OH+ reaction is much lower than those of the H-2 + OH+ and HD + OH+ reactions, which are quite close.