The energy dependence of forward pion double charge exchange reactions on light nuclei is studied for both the ground state transition and the double-isobaric-analog-state transitions. A common characteristic of these double reactions is a resonancelike peak around $50\phantom{\rule{0.3em}{0ex}}\text{MeV}$ pion laboratory energy. This peak arises naturally in a two-step process in the conventional pion-nucleon system with proper handling of nuclear structure and pion distortion. A comparison among the results of different nuclear structure models demonstrates the effects of configuration mixing. The angular distribution is used to fix the single-particle wave function.