1) Cultus is a powerful work horse with no safety or security features and old shape . Fuel economy, A/C , suspension and brakes are average.
2) Wagon r is good. It's basically new cultus with a different body shape. Fuel economy is great thanks to newer technology engine and is also pretty powerful. You can easily drive this car on longer routes. A/C performance is just amazing. It's only downside is it's shape which is like a DABBA.
3) Alto is a really nice car. modern design with fuel efficent engine being adequately powerful. A/C is good in 660cc category. Seats are comfortable, rear leg room is too good. Features like immoblizer and airbags are present as well.
Now my opinion is to go for cultus only if u want to save some cash, u can easily get a nice ride in 11 lac otherwise it's obsolete.Regarding wagon r and alto u will need to see your priorities first. If u are a local commuter who wants fuel efficiency then go for alto otherwise wagon r is the best of both worlds.