With language of this tripartite agreement, I am almost certain that this is not authority's standard agreement template. Builder is saying that they have to get this agreement approved from authority before they could get anyone's registry. (I am not even sure if they are correct here).
About this you can obtain information from NDA through RTI act too instead of making wild guesses.
) I am worried that tripartite agreement will supersede any kind addendum to original agreement or any different agreement so even if they write anything on addendum my problem (2) won't be fixed by it.
2) Is there any way to work it around? For e.g. if we do a third agreement after our tripartite agreement and referring to our original agreement and tripartite agreement, will this third agreement supersede registered tripartite agreement?
First of all the builder says that it is mandatory to obtain approval from authority by executing a tripartite agreement. If that is the case how do you think that you can enter into a third agreement after finalising the tripartite agreement? If the builder says that he can make an addendum to the original agreement, how will it be enforceable because upon drawing a new tripartite agreement which supersedes the previous agreement, the previous agreement becomes infructuous and no addendum can be added to an infructuous agreement. Instead of addendum, whether the builder is agreeing to make good the promised facilities and is ready to enter into an agreement to that aspect alone, if so, get it executed and registered separately.
3) What is correct way of getting this third agreement ready? I mean are two witness enough or do I also need to get a witness from an advocate or get it notarized or something?
Get it registered so that validity is added to it in the event of builder failing to keep his promise at a later stage.
I am finding it very difficult to find an good advocate that does not charge a bomb. I am a law student myself but have no real experience and work only on labour/hr related laws.
You can prepare a draft of the proposed agreement and get it verified from a good lawyer in the local or from any of the lawyer of this forum on private consultations.