Discrepancies of name of a person

1. My father is a Central Govt. pensioner. In all his educational documents, Pension Payment Order (PPO), Aadhaar Card, Pan Card, all Bank Accounts (joint accounts with my mother i.e., his wife) and investments, his name has been mentioned as Alok Kumar Chattopadhyay . He also owns a house in the name of Alok Kumar Chattopadhyay. 2. However in Voter ID card, Ration Card his name is mentioned as Alok Chatterjee. 3. In all the Bank Accounts and PPO the surname of his wife is Chatterjee. 4. In all his Bank Accounts and investments nominees are his wife/son/daughter (myself) having their surname as Chatterjee. 5. In Aadhaar Card, PAN Card, surname of his wife is Chatterjee with her father’s name and in voter ID Card and Ration Card, husband’s name is Alok Chatterjee with her surname as Chatterjee. 6. His son and daughter i.e., my elder brother and I are using Chatterjee as our surname in all our documents such as Aadhar cards, Pan Cards, Passports, Voter I cards, all bank accounts, Investments etc, wherein our father’s name is mentioned as Alok Chatterjee. His son is employed in corporate sector having mediclaim policy wherein father’s name is Alok Chatterjee. So in nutshell, he is using Chattopadhyay as his surname in some of the documents and in some other documents he is also using Chatterjee as his surname. However his son and daughter are using the name Alok Chatterjee as their legal guardian in all their documents. His spouse in some places states that Alok Chatterjee is her husband’s name and somewhere she mentions that the name of her husband is Alok Kumar Chattopadhyay. In Bengali Brahmin community, Chattopadhyay and Chatterjee represents the same surname. He has already made an affidavit before Hon’ble 1st Class Judicial Magistrate that Alok Kumar Chattopadhyay and Alok Chatterjee is same and identical person and also in the same affidavit He has declared that his wife, son and daughter who are using their surname as Chatterjee are his legal heirs indicating their names, relationships and dates of birth. In the light of above please guide me. My queries are: a) What will be the consequences to be faced by all of his family members? b) Whether the affidavit made for different purposes in same one is legally valid and will serve in future to overcome the discrepancies of his name in various documents. c) Whether there will be any difficulties in future for inheritance of his movable/immovable properties in his presence/absence. d) As at this stage it is difficult to change/correct any name/surname in any document, what actions to be taken and/or procedures to be followed to overcome all the litigations in future smoothly in his presence /absence which will be legally valid. e) May he make any will or gift deed and how.