1. You can get your names mutated for paying the Municipal Tax but you are required to register the sale deed of the property in the joint names of all the legal heirs of your father.
2. Without OC/CC, Registrar will refuse to register the property.
3. Try to get the OC/CC first and for any deviation construction from the sanction plan, the Municipal Corporation might ask for penalty at specified rate and after payment of the same, CC/OC might be issued by the said Municipal Corporation.
4. Once the said OC/CC is availed, the subsequent steps to register the sale deed in favour of all the legal heirs of your father can be taken to enable you top resale the said property to a third party.
5. Without registering the property in your names also you can sell it of by asking the builder to sell the title deed in favour of your buyer wherein yoiu shall have to sign as confirming party or witness.