I have driven all of the above cars and i will go for Cultus without a second thought.
It has better interior and exterior design.
More powerful engine then all of these.
More cabin space plus soft suspension.
Mileage of Cultus EFI will be between 11-13KM/Ltr (depends upon your driving style). Alto and Coure both gives bad mileage according to their engine.
And in 900K it will be really hard to find Good Passo or vitz so i would Prefer to buy Cultus or take your 2nd option as Suzuki Cervo ( I like it personally).