Hello,
1) By virtue of the registration through the intervention of the court you have become rightful owner of the property. I suppose that the POA was registered and competent to execute the sale in the first place, because the court passed the order on the basis that the sale would have been executed had the the POA been present.
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2)The Original owner revoking the POA in no way will impeach your right you acquired through the Registered Sale Deed.All the the POA did while the POA was in effect is binding on the principal and can not deny your rights acquired.
3) It is unlikely that the people who did forgery and made duplicate documents would succeed as the POA has already moved against them.The law will take its own course in adjudicating on the forgery committed in separate case and yourrights are not going to be impeached as a result..
4) As far as the sale that the POA has done of the same property at a previous date can pose serious challenge to your title.As a POA he had the right to execute such transfer.You ought to have done a property search before you purchased the land.The search would bring before you clearly the status of the property in terms of title.
You need to proceed with a case of cheating against the POA and the actual owner the principal.
5) Besides all the above do implead youself in all the cases as your interests are at stake as far as the property is concerned.