Title suit

You have only proper option go for Adverse Possession against all relatives or whoever are claiming any rights in property

Since you are in possession as per my knoweldge cause of action can be taken now also because your can present dispute started now but don't delay the matter, file the adverse possession suit soon without thinking. 

If issues are not settled or witness exhamination not started then you can amend the Plaint showing some or other proper reason and by adding proper court fee and then they will file written statement and whole thing will be like restarting whole suit . 

You should have all evidence to prove that your family was residing on that property for long time

By invoking Benanmi transaction act honestly myself bit confused why they did so, because they could have filled tresspass case against you since property was in their name.

It seems they are tring to make situation that neither my property nor your property some thing like that. There is some other propsed amendment to benanmi transaction act pending in parliament till the bill is not passed we can never say what will change. You know our Parliament very well 

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Don't mess with Benanmi Transaction prohibition act because 

Sec 5 of act states

Property held benami liable to acquisition. -

(1)       All properties held benami shall be subject to acquisition by such authority, in Such manner  and  after following shelf procedure, as may be prescribed.

(2)       For the removal of doubts, it is hereby declared that no amount shall he payable for the acquisition of any property under sub-section (1)