My cousin has left that place and somebody else lives there now. My question is that during police investigation, will my cousin be interrogated? Will the police reveal to her the whole case? What are the questions she would be asked?
Your cousin who was the owner/tenant of that house at the time of incidence may be interrogated.
The questions to be asked from your sister will depend, normally a woman cop will record the details.
Also, we have recently shifted to a new place. And have got the permanent address changed on our IDs, which will be used in the complaint. My fear is that when the accused will appeal in the higher courts, he will use the old permanent address only since he knew that one. So my question is, can he use any address of his own choice at the time of appealing or will he be liable to use the one provided in the complaint? At our old permanent address, my extended family stays and i surely don't want the court notice to come there.
The question of address is not essential at this stage.
The complaint if lodged now, it will take years to get disposed in the court of law.
After this, in case the accused decides to prefer an appeal then a notice would be sent to your given address or the available address.
If the notice is returned undelivered for want of proper address, then the court may pass an order to furnish fresh address.
You may carefully file a caveat petition in advance, before high court which will take care of the address problem.