Regarding the Marriage / Birth certificate of spouse / kid, I have done both and in both cases I never did the attestation of Bahrain Embassy in Pakistan. From Pakistan the only attestation I did was from MOFA Pakistan, via Leopards Courier Service. And from Bahrain I did the attestation from Pakistan Embassy and then from MOFA Bahrain (Manama Center), and then applied for visa. No issue at all.
I believe that you have an option, either to get attestation from Bahrain Embassy in Pakistan OR MOFA Bahrain, not both. Better to check with your agent / PRO first to save the hassle.