How difficult is it for a non-trained movie actor to execute classical steps for the camera?

It depends on the ability of the choreographer and the director to make the shots look perfect. For the actor, it is not difficult to perform the dance in bits and look good;of course one has to take pains to practice.

How often do dance directors use trained doubles to show footwork in close-up ?

Quite often, in fact more than often. Even in full long shots, where the face of heroine is not very clearly visible, the service of expert dancers is used.

Which actor today can pull off classical choreography without a double?

In my time there were quite a few - Vyjayanthimala, Padmini, Waheeda Rehman, Sandhya, Asha Parekh. Then came Hema Malini, Sridevi Madhuri Dixit and Jaya Prada. Today...well, you can see for yourself.

How much did you contribute to Pakeezah's mujras?

I have deep respect for Meena Kumari so I don't want to go into too many details. But I was her double in songs where her face is not clearly visible and where the focus is on the feet. Chalo dildaar chalo and Aaj hum apni duaaon ka asar, for instance. Another reason I agreed to do the double was because Meenaji was very ill those days.