1. not necessary to mention the survey numbers
2. only sufficient details of the property which would help identify that property
3. ensure that the witnesses are young. as old witnesses may die and thus may be unavailable to depose in court if the Will is put to proof
4. not necessary to register the Will
5. witnesses can be any persons. but see to it that they are easily available when required in order to depose in court about attestation of the Will and that its genuine
6. i advise you take affidavits from the witnesses beforehand describing how the Will was executed by the father and how the witnesses attested to it. This will ensure that if in future the witnesses are not available for some reasons, you can use their affidavits in Court for proving the Will in case the Will is challenged by your sister or some other person