The entire steering wheel can be replaced with a smaller one to ensure a correct grip.
If reaching the pedals is an issue the gas, brake and clutch pedal can be moved within reach by the use of extension pedals. If people of different height share the same vehicle, the pedal extensions can be made foldable or detachable.
The car seat itself can be adapted with various inserts to reduce the seat depth. Higher seat cushions, tilted seat cushions and so on.