Need advice on Agreement.

I have finalized a property in Under construction apartment (Possession in next 6 month) and I have taken copy of sample agreement for checking. The society having 3 buildings, 2 are already ready and builder has given possession also, and for 3rd builder is assuring to give possession in next 6 months. The builder is having a firm of around 8 partners and the land owner also have many flat on his own name in the under construction building. I have few questions – 1. For agreement, builder is saying that bcoz it's land owner flat, so the agreement b/w land owner and purchaser only will be executed and builder will not involve in that.. is it legally correct..builder can claim anything later on this type of flat or it' s safe to buy? 2. The project is already approved from some reputed bank (hdfc, sbi) but builder is saying i can't take loan from other banks (pnb or BOM), because the Title search document is not clear for 30 years, they have only for last 15 yrs. (Builder is saying the original title search documents they submitted in SBI before 2 yrs and now they don't have so forcing to take loan from already approved banks only). Is it fine to buy with 15 yrs Title search? 3. In agreement, the builder has added clause that he can develop other floors on terrace, can use amenity and parking space even after forming the society, is it legal? 4. Is it mandatory for a builder to form apartment association/Society and what action we can take if builder is not forming it? And during the society formation builder needs to transfer the land ownership to the Society or he can still in force of ownership of the land. and how/by which document we can check that builder is going to transfer the land or not to the Society during society formation?