Ever means for all time. Forever. The person may never go back to their hometown for as long as they live. What is stopping the person going back? "Would I..." asks if that's something a particular person would do in an introspective way. "Would I help somebody if they were in trouble." "Will I..." considers if something will happen in the future. "Will I ever get married?" "Could I..." and "Can I..." suggests there is something stopping the person going back. Perhaps they did something wrong and are not welcome now. Informally ever can also be put at the end of these sentences to emphasise that it may not happen for as long as they'll live. "Will I return to my hometown, ever"