Can some Indian member tell me some Brahmin surnames and which part of India they are usually found in, usually which sect they belong to/god they worship and what language they speak?
It is difficult. There are many Muslims who were converted to Islam who retain their Brahmin Hindu surnames.
You find last names such as Kelkar, Joshi, Bhat, Modak, Pradhan etc but with Muslim first names.
Similarly th Portuguese converted many Hindus to Christians in Goa etc where many Christians have Saraswat Brahmin surnames like Prabhu etc.