Oh I see. Well, you don't have to worry about it that much. Its not a major issue. You won't be questioned because the information is legal.
1) As long as there isn't any mismatch of the DOB in your docs, you're fine. Thus, with the available valid information the gap of 4 months will be considered genuine.
2) You will have to get a "Same name affidavit" for two types of family names used in your docs (agarwal and aggarwal).
3) You don't need an affidavit for your father's name difference if only one type of his name has been used throughout YOUR ALL DOCUMENTS. Keep everything in sync with your OWN docs only!
That's fine. I can understand your scenario. Each case is full of complications, yours is no different. So, don't worry about it. Go ahead with your queries and doubts, we'll try to help as much as we can. Even you can ping me separately. Good luck Dear