As per Regulation the Fungible for Rehab isFree to the extent of 35% of their existing area and canot be used for Sale. However Legally areas can be sold and a way be deviced to do so
You will require an NOC ffrom the bank prior to buying such property. You can make payment of the balance dues of the bank from the agreed value of the flat to the Bank directly and thereupon you can also get the originals of the flat from the bank. The original documents of the Flat will not be required at the time of registration of your agreement/sale deed.
No objection certificate inter alia certifying that the member selling the flat has no dues and that the society has no objection for the sale by such member.
It will all depend on the title of the builder to the land in question. Nationalised Banks are usually very cautious while dispossing such loan. However, financial institutions are aggressive in that connection.
Yes, if you are an Indian National, then you could execute such Power of Attorney before the Indian Emabassy and forward the same here for adjudication and payment of stamp duty.