I believe fuel average wise cultus is the best option. Cons are less interior space and cheap plastics. Suspension is on the stiffer side but improved handling due to stiffness. Great engine.
Picanto is not good on feul but good in quality of materials and comfort.
Wagon R is good in space, materials and engine but the shape is a personal preference Also it has good suspension but rear tends to bounce with load in the back.
your other options are vitz and Passo.
Both good cars but they will be used and documents checking is something thats needs proper verification.