Yeah, u can do it. u need few modifications. As for solar power u need to have a solar panel with good efficiency and a good storage battery. the parameters of battery and wattage of panel will depend on the quality of car u need( speed and load).
U need a electric motor and a LPG engine to give a mechanical work to the wheel. Here u need a modified gear box which can easily move from electric motor to lpg and vice versa. So the main focus u need is to design a gear box.
Best of luck