1. POA was valid on 7th March 2014 or not ?
POA deed as you said was registered on 11 Mar 2013, is valid as on 07.03.2014;
2. 11 months 29 days calculation will start from 8th March or 11th March ?
We will give the benefit of doubt to the POA holder and can hold the date of registration as effective date.
3. If POA was valid, and if the builder can execute the sale deed, can it be presented for registration within 04 months ?
Now you should see if the POA deed is valid as on the date of registration of sale deed though the fact is that it can be registered within 4 months from the date of execution. Whether the vendor (the POA agent) has marketable title (effective POA deed) as on the date of registration of sale deed.
4. During presentation of sale deed for registration, the POA was expired but as the builder had originally executed the sale deed when POA was vaild , is he competent enough to present the sale deed document at the registrar's office.
Why do you repeat the same question in a different form? See the above answer which suits for this question too.
5. Builder is saying that he will give an notorised affadavit of all 03 land owners that they have recieved the money from that sale and have no future interest in that land. Is that enough or not ?
Please advise as I am getting very confused.
This notarised affidavit or any NOC cannot be enforceable legally and shall not be admissible as evidence in law in the event of any litigation in future in this regard.
The notarised affidavit is not binding on the original vendors, if they decide to challenge it in he future then you dont have rounds to defend your case.
Better ask them to execute a ratification deed and get it registered properly instead of entering into an argument with the agent/builder, if he is not listening you may lodge a criminal complaint against him for cheating offences informing that he sold the property without any authority or marketable title hence to initiate legal action against him for the said offences, this will take care of other issues.